diff --git a/app/src/main/res/values-de-rAT/strings.xml b/app/src/main/res/values-de-rAT/strings.xml
index b05535ee0a..04d9cbec34 100644
--- a/app/src/main/res/values-de-rAT/strings.xml
+++ b/app/src/main/res/values-de-rAT/strings.xml
@@ -1210,6 +1210,7 @@ Protokolle, die dem Standard nicht entsprechen, wie „Microsoft Exchange Web Se
     <string name="title_fix">Problem beheben</string>
     <string name="title_enable">Aktivieren</string>
     <string name="title_enabled">Aktiviert</string>
+    <string name="title_disable">Deaktivieren</string>
     <string name="title_executing">Wird ausgeführt</string>
     <string name="title_completed">Fertig</string>
     <string name="title_default_changed">Standard geändert</string>
diff --git a/app/src/main/res/values-de-rDE/strings.xml b/app/src/main/res/values-de-rDE/strings.xml
index b05535ee0a..04d9cbec34 100644
--- a/app/src/main/res/values-de-rDE/strings.xml
+++ b/app/src/main/res/values-de-rDE/strings.xml
@@ -1210,6 +1210,7 @@ Protokolle, die dem Standard nicht entsprechen, wie „Microsoft Exchange Web Se
     <string name="title_fix">Problem beheben</string>
     <string name="title_enable">Aktivieren</string>
     <string name="title_enabled">Aktiviert</string>
+    <string name="title_disable">Deaktivieren</string>
     <string name="title_executing">Wird ausgeführt</string>
     <string name="title_completed">Fertig</string>
     <string name="title_default_changed">Standard geändert</string>
diff --git a/app/src/main/res/values-de-rLI/strings.xml b/app/src/main/res/values-de-rLI/strings.xml
index b05535ee0a..04d9cbec34 100644
--- a/app/src/main/res/values-de-rLI/strings.xml
+++ b/app/src/main/res/values-de-rLI/strings.xml
@@ -1210,6 +1210,7 @@ Protokolle, die dem Standard nicht entsprechen, wie „Microsoft Exchange Web Se
     <string name="title_fix">Problem beheben</string>
     <string name="title_enable">Aktivieren</string>
     <string name="title_enabled">Aktiviert</string>
+    <string name="title_disable">Deaktivieren</string>
     <string name="title_executing">Wird ausgeführt</string>
     <string name="title_completed">Fertig</string>
     <string name="title_default_changed">Standard geändert</string>
diff --git a/app/src/main/res/values-el-rGR/strings.xml b/app/src/main/res/values-el-rGR/strings.xml
index 4bed9e2a1f..9f1e0a6ed7 100644
--- a/app/src/main/res/values-el-rGR/strings.xml
+++ b/app/src/main/res/values-el-rGR/strings.xml
@@ -1203,6 +1203,7 @@
     <string name="title_fix">Επιδιόρθωση</string>
     <string name="title_enable">Ενεργοποίηση</string>
     <string name="title_enabled">Ενεργοποιημένο</string>
+    <string name="title_disable">Απενεργοποίηση</string>
     <string name="title_executing">Εκτελείται</string>
     <string name="title_completed">Ολοκληρώθηκε</string>
     <string name="title_default_changed">Η προεπιλογή έχει αλλάξει</string>
diff --git a/app/src/main/res/values-es-rES/strings.xml b/app/src/main/res/values-es-rES/strings.xml
index 63702ad44b..263a21c85b 100644
--- a/app/src/main/res/values-es-rES/strings.xml
+++ b/app/src/main/res/values-es-rES/strings.xml
@@ -1213,6 +1213,7 @@
     <string name="title_fix">Reparar</string>
     <string name="title_enable">Activar</string>
     <string name="title_enabled">Activado</string>
+    <string name="title_disable">Desactivar</string>
     <string name="title_executing">En ejecución</string>
     <string name="title_completed">Completado</string>
     <string name="title_default_changed">Por defecto cambió</string>
diff --git a/app/src/main/res/values-fr-rCA/strings.xml b/app/src/main/res/values-fr-rCA/strings.xml
index 7368c7c06c..3372094ce6 100644
--- a/app/src/main/res/values-fr-rCA/strings.xml
+++ b/app/src/main/res/values-fr-rCA/strings.xml
@@ -1212,6 +1212,7 @@
     <string name="title_fix">Corriger</string>
     <string name="title_enable">Activer</string>
     <string name="title_enabled">Activé</string>
+    <string name="title_disable">Désactiver</string>
     <string name="title_executing">Exécution en cours</string>
     <string name="title_completed">Terminé</string>
     <string name="title_default_changed">Valeur par défaut modifiée</string>
diff --git a/app/src/main/res/values-fr-rFR/strings.xml b/app/src/main/res/values-fr-rFR/strings.xml
index e9d0d37027..80a46f69d7 100644
--- a/app/src/main/res/values-fr-rFR/strings.xml
+++ b/app/src/main/res/values-fr-rFR/strings.xml
@@ -1212,6 +1212,7 @@
     <string name="title_fix">Corriger</string>
     <string name="title_enable">Activer</string>
     <string name="title_enabled">Activé</string>
+    <string name="title_disable">Désactiver</string>
     <string name="title_executing">Exécution en cours</string>
     <string name="title_completed">Terminé</string>
     <string name="title_default_changed">Valeur par défaut modifiée</string>
diff --git a/app/src/main/res/values-nl-rNL/strings.xml b/app/src/main/res/values-nl-rNL/strings.xml
index 7046eaa305..4b4173a1f7 100644
--- a/app/src/main/res/values-nl-rNL/strings.xml
+++ b/app/src/main/res/values-nl-rNL/strings.xml
@@ -1211,6 +1211,7 @@
     <string name="title_fix">Oplossen</string>
     <string name="title_enable">Inschakelen</string>
     <string name="title_enabled">Ingeschakeld</string>
+    <string name="title_disable">Uitschakelen</string>
     <string name="title_executing">Aan het uitvoeren</string>
     <string name="title_completed">Voltooid</string>
     <string name="title_default_changed">Standaard gewijzigd</string>
diff --git a/app/src/main/res/values-pl-rPL/strings.xml b/app/src/main/res/values-pl-rPL/strings.xml
index 529344e825..9f23898783 100644
--- a/app/src/main/res/values-pl-rPL/strings.xml
+++ b/app/src/main/res/values-pl-rPL/strings.xml
@@ -1233,6 +1233,7 @@
     <string name="title_fix">Popraw</string>
     <string name="title_enable">Włącz</string>
     <string name="title_enabled">Włączone</string>
+    <string name="title_disable">Wyłącz</string>
     <string name="title_executing">Wykonywanie</string>
     <string name="title_completed">Ukończone</string>
     <string name="title_default_changed">Zmieniono wartość domyślną</string>
diff --git a/app/src/main/res/values-pt-rPT/strings.xml b/app/src/main/res/values-pt-rPT/strings.xml
index fd055b97d0..72e6c50b21 100644
--- a/app/src/main/res/values-pt-rPT/strings.xml
+++ b/app/src/main/res/values-pt-rPT/strings.xml
@@ -15,6 +15,7 @@
     <string name="channel_error">Erros</string>
     <string name="channel_alert">Alertas do servidor</string>
     <string name="channel_group_contacts">Contactos</string>
+    <string name="channel_service_description">A sincronização e monitorização de contas</string>
     <string name="channel_send_description">Envio de mensagens</string>
     <string name="channel_notification_description">Notificações de novas mensagens</string>
     <plurals name="page_conversation">
@@ -193,6 +194,7 @@
     <string name="title_setup_theme_red_green">Vermelho/verde</string>
     <string name="title_setup_theme_grey">Cinzento</string>
     <string name="title_setup_theme_black">Preto</string>
+    <string name="title_setup_theme_black_and_white">Preto e Branco</string>
     <string name="title_setup_theme_reverse">Inverter cores</string>
     <string name="title_setup_theme_dark">Escuro</string>
     <string name="title_setup_theme_system">Seguir o sistema</string>
@@ -230,6 +232,7 @@
     <string name="title_advanced_sync_folders">Sincronizar lista de pastas</string>
     <string name="title_advanced_sync_shared_folders">Sincronizar lista de pastas partilhadas</string>
     <string name="title_advanced_subscriptions">Gerir subscrições de pastas</string>
+    <string name="title_advanced_sync_subscribed">Sincronizar automaticamente as pastas subscritas</string>
     <string name="title_advanced_check_mx">Verificar endereços de e-mail do remetente ao sincronizar mensagens</string>
     <string name="title_advanced_check_reply">Verificar endereços de e-mail de resposta ao sincronizar mensagens</string>
     <string name="title_advanced_tune_keep_alive">Ajustar automaticamente o intervalo de manutenção de connexão</string>
@@ -384,8 +387,11 @@
     <string name="title_advanced_language_detection">Detectar idioma do texto da mensagem</string>
     <string name="title_advanced_fts">Construir índice de pesquisa</string>
     <string name="title_advanced_fts_indexed">%1$d / %2$d mensagens indexadas (%3$s)</string>
+    <string name="title_advanced_language">Idioma</string>
+    <string name="title_advanced_language_system">Sistema</string>
     <string name="title_advanced_watchdog">Verificar periodicamente se o FairEmail ainda está ativo</string>
     <string name="title_advanced_optimize">Otimizar automaticamente</string>
+    <string name="title_advanced_updates">Verificar atualizações do GitHub</string>
     <string name="title_advanced_experiments">Ativar funcionalidades experimentais</string>
     <string name="title_advanced_query_threads">Limitar acesso paralelo à base de dados</string>
     <string name="title_advanced_crash_reports">Enviar relatórios de erro</string>
diff --git a/app/src/main/res/values-sv-rSE/strings.xml b/app/src/main/res/values-sv-rSE/strings.xml
index 835f658cd1..b16056d4b8 100644
--- a/app/src/main/res/values-sv-rSE/strings.xml
+++ b/app/src/main/res/values-sv-rSE/strings.xml
@@ -1211,6 +1211,7 @@
     <string name="title_fix">Åtgärda</string>
     <string name="title_enable">Aktivera</string>
     <string name="title_enabled">Aktiverad</string>
+    <string name="title_disable">Inaktivera</string>
     <string name="title_executing">Kör</string>
     <string name="title_completed">Slutförd</string>
     <string name="title_default_changed">Standard ändrad</string>
diff --git a/app/src/main/res/values-zh-rCN/strings.xml b/app/src/main/res/values-zh-rCN/strings.xml
index ca962af5ac..ac08efee2c 100644
--- a/app/src/main/res/values-zh-rCN/strings.xml
+++ b/app/src/main/res/values-zh-rCN/strings.xml
@@ -1200,6 +1200,7 @@
     <string name="title_fix">修复</string>
     <string name="title_enable">启用</string>
     <string name="title_enabled">已启用</string>
+    <string name="title_disable">禁用</string>
     <string name="title_executing">执行中</string>
     <string name="title_completed">完成</string>
     <string name="title_default_changed">默认已更改</string>
diff --git a/docs/FAQ-af-rZA.md b/docs/FAQ-af-rZA.md
index 7b7b451250..a593607a58 100644
--- a/docs/FAQ-af-rZA.md
+++ b/docs/FAQ-af-rZA.md
@@ -78,6 +78,7 @@ Related questions:
 * A preview of a message text doesn't (always) appear on Samsung watches because [setLocalOnly](https://developer.android.com/reference/androidx/core/app/NotificationCompat.Builder.html#setLocalOnly(boolean)) seem to be ignored. Message preview texts are known to be displayed correctly on Pebble 2, Fitbit Charge 3, Mi band 3, and Xiaomi Amazfit BIP wearables. See also [this FAQ](#user-content-faq126).
 * A [bug in Android 6.0](https://issuetracker.google.com/issues/37068143) causes a crash with *... Invalid offset: ... Valid range is ...* when text is selected and tapping outside of the selected text. This bug has been fixed in Android 6.0.1.
 * Internal (anchor) links will not work because original messages are shown in an embedded WebView in a scrolling view (the conversation list). This is an Android limitation which cannot be fixed or worked around.
+* Language detection [is not working anymore](https://issuetracker.google.com/issues/173337263) on Pixel devices with (upgraded to?) Android 11
 
 ## Planned features
 
@@ -861,7 +862,7 @@ The error *... Connection refused ...* means that the email server or something
 
 The error *... Network unreachable ...* means that the email server was not reachable via the current internet connection, for example because internet traffic is restricted to local traffic only.
 
-The error *... Host is unresolved ...* or "*... Unable to resolve host ...* means that the address of the email server could not be resolved. This might be caused by ad blocking or an unreachable or not properly working [DNS](https://en.wikipedia.org/wiki/Domain_Name_System) server.
+The error *... Host is unresolved ...*, *... Unable to resolve host ...* or *... No address associated with hostname ...* means that the address of the email server could not be resolved into an IP address. This might be caused by a VPN, ad blocking or an unreachable or not properly working (local) [DNS](https://en.wikipedia.org/wiki/Domain_Name_System) server.
 
 The error *... Software caused connection abort ...* means that the email server or something between FairEmail and the email server actively terminated an existing connection. This can for example happen when connectivity was abruptly lost. A typical example is turning on flight mode.
 
@@ -2162,14 +2163,12 @@ Disabling *Partial fetch* will result in more memory usage.
 <a name="faq111"></a>
 **(111) Is OAuth supported?**
 
-OAuth for Gmail is supported via the quick setup wizard. The Android account manager will be used to fetch and refresh OAuth tokens for selected on-device accounts. OAuth for non on-device accounts is not supported because Google requires a [yearly security audit](https://support.google.com/cloud/answer/9110914) ($15,000 to $75,000) for this.
+OAuth for Gmail is supported via the quick setup wizard. The Android account manager will be used to fetch and refresh OAuth tokens for selected on-device accounts. OAuth for non on-device accounts is not supported because Google requires a [yearly security audit](https://support.google.com/cloud/answer/9110914) ($15,000 to $75,000) for this. You can read more about this [here](https://www.theregister.com/2019/02/11/google_gmail_developer/).
 
-OAuth for Yandex is supported via the quick setup wizard.
+OAuth for Yandex and Yahoo is supported via the quick setup wizard.
 
 OAuth for Office 365 accounts is supported, but Microsoft does not offer OAuth for Outlook, Live and Hotmail accounts (yet?).
 
-OAuth access for Yahoo was requested, but Yahoo never responded to the request. OAuth for AOL [was deactivated](https://www.programmableweb.com/api/aol-open-auth) by AOL. Verizon owns both AOL and Yahoo, collectively named [Oath inc](https://en.wikipedia.org/wiki/Verizon_Media). So, it is reasonable to assume that OAuth is not supported by Yahoo anymore too.
-
 <br />
 
 <a name="faq112"></a>
@@ -2302,8 +2301,6 @@ FairEmail groups messages based on the standard *Message-ID*, *In-Reply-To* and
 
 When FairEmail cannot connect to an email server to receive messages, for example when the internet connection is bad or a firewall or a VPN is blocking the connection, FairEmail will wait 8, 16 and 32 seconds while keeping the device awake (=use battery power) and try again to connect. If this fails, FairEmail will schedule an alarm to retry after 15, 30 and 60 minutes and let the device sleep (=no battery usage).
 
-Between connectivity changes there is a wait of 90 seconds to give the email server the opportunity to discover the old connection is broken. This is necessary because the internet connection of a mobile device is often lost abruptly and to prevent the problem described in [this FAQ](#user-content-faq23).
-
 Note that [Android doze mode](https://developer.android.com/training/monitoring-device-state/doze-standby) does not allow to wake the device earlier than after 15 minutes.
 
 *Force sync* in the three-dots menu of the unified inbox can be used to let FairEmail attempt to reconnect without waiting.
@@ -2777,6 +2774,8 @@ Updating once a week will probably be sufficient, please see [here](https://gith
 
 Permanent deletion means that messages will *irreversibly* be lost, and to prevent this from happening accidentally, this always needs to be confirmed. Even with a confirmation, some very angry people who lost some of their messages through their own fault contacted me, which was a rather unpleasant experience :-(
 
+Advanced: the IMAP delete flag in combination with the EXPUNGE command is not supportable because both email servers and not all people can handle this, risking unexpected loss of messages. A complicating factor is that not all email servers support [UID EXPUNGE](https://tools.ietf.org/html/rfc4315).
+
 <br />
 
 <a name="faq161"></a>
diff --git a/docs/FAQ-ar-rBH.md b/docs/FAQ-ar-rBH.md
index 8f53761f21..b8932c6f45 100644
--- a/docs/FAQ-ar-rBH.md
+++ b/docs/FAQ-ar-rBH.md
@@ -78,6 +78,7 @@ Related questions:
 * A preview of a message text doesn't (always) appear on Samsung watches because [setLocalOnly](https://developer.android.com/reference/androidx/core/app/NotificationCompat. Builder.html#setLocalOnly(boolean)) seem to be ignored. Message preview texts are known to be displayed correctly on Pebble 2, Fitbit Charge 3, Mi band 3, and Xiaomi Amazfit BIP wearables. See also [this FAQ](#user-content-faq126).
 * A [bug in Android 6.0](https://issuetracker.google.com/issues/37068143) causes a crash with *... Invalid offset: ... Valid range is ...* when text is selected and tapping outside of the selected text. This bug has been fixed in Android 6.0.1.
 * Internal (anchor) links will not work because original messages are shown in an embedded WebView in a scrolling view (the conversation list). This is an Android limitation which cannot be fixed or worked around.
+* Language detection [is not working anymore](https://issuetracker.google.com/issues/173337263) on Pixel devices with (upgraded to?) Android 11
 
 ## Planned features
 
@@ -861,7 +862,7 @@ The error *... Connection refused ...* means that the email server or something
 
 The error *... Network unreachable ...* means that the email server was not reachable via the current internet connection, for example because internet traffic is restricted to local traffic only.
 
-The error *... Host is unresolved ...* or "*... Unable to resolve host ...* means that the address of the email server could not be resolved. This might be caused by ad blocking or an unreachable or not properly working [DNS](https://en.wikipedia.org/wiki/Domain_Name_System) server.
+The error *... Host is unresolved ...*, *... Unable to resolve host ...* or *... No address associated with hostname ...* means that the address of the email server could not be resolved into an IP address. This might be caused by a VPN, ad blocking or an unreachable or not properly working (local) [DNS](https://en.wikipedia.org/wiki/Domain_Name_System) server.
 
 The error *... Software caused connection abort ...* means that the email server or something between FairEmail and the email server actively terminated an existing connection. This can for example happen when connectivity was abruptly lost. A typical example is turning on flight mode.
 
@@ -2162,14 +2163,12 @@ Disabling *Partial fetch* will result in more memory usage.
 <a name="faq111"></a>
 **(111) Is OAuth supported?**
 
-OAuth for Gmail is supported via the quick setup wizard. The Android account manager will be used to fetch and refresh OAuth tokens for selected on-device accounts. OAuth for non on-device accounts is not supported because Google requires a [yearly security audit](https://support.google.com/cloud/answer/9110914) ($15,000 to $75,000) for this.
+OAuth for Gmail is supported via the quick setup wizard. The Android account manager will be used to fetch and refresh OAuth tokens for selected on-device accounts. OAuth for non on-device accounts is not supported because Google requires a [yearly security audit](https://support.google.com/cloud/answer/9110914) ($15,000 to $75,000) for this. You can read more about this [here](https://www.theregister.com/2019/02/11/google_gmail_developer/).
 
-OAuth for Yandex is supported via the quick setup wizard.
+OAuth for Yandex and Yahoo is supported via the quick setup wizard.
 
 OAuth for Office 365 accounts is supported, but Microsoft does not offer OAuth for Outlook, Live and Hotmail accounts (yet?).
 
-OAuth access for Yahoo was requested, but Yahoo never responded to the request. OAuth for AOL [was deactivated](https://www.programmableweb.com/api/aol-open-auth) by AOL. Verizon owns both AOL and Yahoo, collectively named [Oath inc](https://en.wikipedia.org/wiki/Verizon_Media). So, it is reasonable to assume that OAuth is not supported by Yahoo anymore too.
-
 <br />
 
 <a name="faq112"></a>
@@ -2302,8 +2301,6 @@ FairEmail groups messages based on the standard *Message-ID*, *In-Reply-To* and
 
 When FairEmail cannot connect to an email server to receive messages, for example when the internet connection is bad or a firewall or a VPN is blocking the connection, FairEmail will wait 8, 16 and 32 seconds while keeping the device awake (=use battery power) and try again to connect. If this fails, FairEmail will schedule an alarm to retry after 15, 30 and 60 minutes and let the device sleep (=no battery usage).
 
-Between connectivity changes there is a wait of 90 seconds to give the email server the opportunity to discover the old connection is broken. This is necessary because the internet connection of a mobile device is often lost abruptly and to prevent the problem described in [this FAQ](#user-content-faq23).
-
 Note that [Android doze mode](https://developer.android.com/training/monitoring-device-state/doze-standby) does not allow to wake the device earlier than after 15 minutes.
 
 *Force sync* in the three-dots menu of the unified inbox can be used to let FairEmail attempt to reconnect without waiting.
@@ -2777,6 +2774,8 @@ Updating once a week will probably be sufficient, please see [here](https://gith
 
 Permanent deletion means that messages will *irreversibly* be lost, and to prevent this from happening accidentally, this always needs to be confirmed. Even with a confirmation, some very angry people who lost some of their messages through their own fault contacted me, which was a rather unpleasant experience :-(
 
+Advanced: the IMAP delete flag in combination with the EXPUNGE command is not supportable because both email servers and not all people can handle this, risking unexpected loss of messages. A complicating factor is that not all email servers support [UID EXPUNGE](https://tools.ietf.org/html/rfc4315).
+
 <br />
 
 <a name="faq161"></a>
diff --git a/docs/FAQ-ar-rEG.md b/docs/FAQ-ar-rEG.md
index 800734e0ae..2c32d8b1d1 100644
--- a/docs/FAQ-ar-rEG.md
+++ b/docs/FAQ-ar-rEG.md
@@ -78,6 +78,7 @@ Related questions:
 * A preview of a message text doesn't (always) appear on Samsung watches because [setLocalOnly](https://developer.android.com/reference/androidx/core/app/NotificationCompat. Builder.html#setLocalOnly(boolean)) seem to be ignored. Message preview texts are known to be displayed correctly on Pebble 2, Fitbit Charge 3, Mi band 3, and Xiaomi Amazfit BIP wearables. See also [this FAQ](#user-content-faq126).
 * A [bug in Android 6.0](https://issuetracker.google.com/issues/37068143) causes a crash with *... Invalid offset: ... Valid range is ...* when text is selected and tapping outside of the selected text. This bug has been fixed in Android 6.0.1.
 * Internal (anchor) links will not work because original messages are shown in an embedded WebView in a scrolling view (the conversation list). This is an Android limitation which cannot be fixed or worked around.
+* Language detection [is not working anymore](https://issuetracker.google.com/issues/173337263) on Pixel devices with (upgraded to?) Android 11
 
 ## Planned features
 
@@ -861,7 +862,7 @@ The error *... Connection refused ...* means that the email server or something
 
 The error *... Network unreachable ...* means that the email server was not reachable via the current internet connection, for example because internet traffic is restricted to local traffic only.
 
-The error *... Host is unresolved ...* or "*... Unable to resolve host ...* means that the address of the email server could not be resolved. This might be caused by ad blocking or an unreachable or not properly working [DNS](https://en.wikipedia.org/wiki/Domain_Name_System) server.
+The error *... Host is unresolved ...*, *... Unable to resolve host ...* or *... No address associated with hostname ...* means that the address of the email server could not be resolved into an IP address. This might be caused by a VPN, ad blocking or an unreachable or not properly working (local) [DNS](https://en.wikipedia.org/wiki/Domain_Name_System) server.
 
 The error *... Software caused connection abort ...* means that the email server or something between FairEmail and the email server actively terminated an existing connection. This can for example happen when connectivity was abruptly lost. A typical example is turning on flight mode.
 
@@ -2162,14 +2163,12 @@ Disabling *Partial fetch* will result in more memory usage.
 <a name="faq111"></a>
 **(111) Is OAuth supported?**
 
-OAuth for Gmail is supported via the quick setup wizard. The Android account manager will be used to fetch and refresh OAuth tokens for selected on-device accounts. OAuth for non on-device accounts is not supported because Google requires a [yearly security audit](https://support.google.com/cloud/answer/9110914) ($15,000 to $75,000) for this.
+OAuth for Gmail is supported via the quick setup wizard. The Android account manager will be used to fetch and refresh OAuth tokens for selected on-device accounts. OAuth for non on-device accounts is not supported because Google requires a [yearly security audit](https://support.google.com/cloud/answer/9110914) ($15,000 to $75,000) for this. You can read more about this [here](https://www.theregister.com/2019/02/11/google_gmail_developer/).
 
-OAuth for Yandex is supported via the quick setup wizard.
+OAuth for Yandex and Yahoo is supported via the quick setup wizard.
 
 OAuth for Office 365 accounts is supported, but Microsoft does not offer OAuth for Outlook, Live and Hotmail accounts (yet?).
 
-OAuth access for Yahoo was requested, but Yahoo never responded to the request. OAuth for AOL [was deactivated](https://www.programmableweb.com/api/aol-open-auth) by AOL. Verizon owns both AOL and Yahoo, collectively named [Oath inc](https://en.wikipedia.org/wiki/Verizon_Media). So, it is reasonable to assume that OAuth is not supported by Yahoo anymore too.
-
 <br />
 
 <a name="faq112"></a>
@@ -2302,8 +2301,6 @@ FairEmail groups messages based on the standard *Message-ID*, *In-Reply-To* and
 
 When FairEmail cannot connect to an email server to receive messages, for example when the internet connection is bad or a firewall or a VPN is blocking the connection, FairEmail will wait 8, 16 and 32 seconds while keeping the device awake (=use battery power) and try again to connect. If this fails, FairEmail will schedule an alarm to retry after 15, 30 and 60 minutes and let the device sleep (=no battery usage).
 
-Between connectivity changes there is a wait of 90 seconds to give the email server the opportunity to discover the old connection is broken. This is necessary because the internet connection of a mobile device is often lost abruptly and to prevent the problem described in [this FAQ](#user-content-faq23).
-
 Note that [Android doze mode](https://developer.android.com/training/monitoring-device-state/doze-standby) does not allow to wake the device earlier than after 15 minutes.
 
 *Force sync* in the three-dots menu of the unified inbox can be used to let FairEmail attempt to reconnect without waiting.
@@ -2777,6 +2774,8 @@ Updating once a week will probably be sufficient, please see [here](https://gith
 
 Permanent deletion means that messages will *irreversibly* be lost, and to prevent this from happening accidentally, this always needs to be confirmed. Even with a confirmation, some very angry people who lost some of their messages through their own fault contacted me, which was a rather unpleasant experience :-(
 
+Advanced: the IMAP delete flag in combination with the EXPUNGE command is not supportable because both email servers and not all people can handle this, risking unexpected loss of messages. A complicating factor is that not all email servers support [UID EXPUNGE](https://tools.ietf.org/html/rfc4315).
+
 <br />
 
 <a name="faq161"></a>
diff --git a/docs/FAQ-ar-rYE.md b/docs/FAQ-ar-rYE.md
index 800734e0ae..2c32d8b1d1 100644
--- a/docs/FAQ-ar-rYE.md
+++ b/docs/FAQ-ar-rYE.md
@@ -78,6 +78,7 @@ Related questions:
 * A preview of a message text doesn't (always) appear on Samsung watches because [setLocalOnly](https://developer.android.com/reference/androidx/core/app/NotificationCompat. Builder.html#setLocalOnly(boolean)) seem to be ignored. Message preview texts are known to be displayed correctly on Pebble 2, Fitbit Charge 3, Mi band 3, and Xiaomi Amazfit BIP wearables. See also [this FAQ](#user-content-faq126).
 * A [bug in Android 6.0](https://issuetracker.google.com/issues/37068143) causes a crash with *... Invalid offset: ... Valid range is ...* when text is selected and tapping outside of the selected text. This bug has been fixed in Android 6.0.1.
 * Internal (anchor) links will not work because original messages are shown in an embedded WebView in a scrolling view (the conversation list). This is an Android limitation which cannot be fixed or worked around.
+* Language detection [is not working anymore](https://issuetracker.google.com/issues/173337263) on Pixel devices with (upgraded to?) Android 11
 
 ## Planned features
 
@@ -861,7 +862,7 @@ The error *... Connection refused ...* means that the email server or something
 
 The error *... Network unreachable ...* means that the email server was not reachable via the current internet connection, for example because internet traffic is restricted to local traffic only.
 
-The error *... Host is unresolved ...* or "*... Unable to resolve host ...* means that the address of the email server could not be resolved. This might be caused by ad blocking or an unreachable or not properly working [DNS](https://en.wikipedia.org/wiki/Domain_Name_System) server.
+The error *... Host is unresolved ...*, *... Unable to resolve host ...* or *... No address associated with hostname ...* means that the address of the email server could not be resolved into an IP address. This might be caused by a VPN, ad blocking or an unreachable or not properly working (local) [DNS](https://en.wikipedia.org/wiki/Domain_Name_System) server.
 
 The error *... Software caused connection abort ...* means that the email server or something between FairEmail and the email server actively terminated an existing connection. This can for example happen when connectivity was abruptly lost. A typical example is turning on flight mode.
 
@@ -2162,14 +2163,12 @@ Disabling *Partial fetch* will result in more memory usage.
 <a name="faq111"></a>
 **(111) Is OAuth supported?**
 
-OAuth for Gmail is supported via the quick setup wizard. The Android account manager will be used to fetch and refresh OAuth tokens for selected on-device accounts. OAuth for non on-device accounts is not supported because Google requires a [yearly security audit](https://support.google.com/cloud/answer/9110914) ($15,000 to $75,000) for this.
+OAuth for Gmail is supported via the quick setup wizard. The Android account manager will be used to fetch and refresh OAuth tokens for selected on-device accounts. OAuth for non on-device accounts is not supported because Google requires a [yearly security audit](https://support.google.com/cloud/answer/9110914) ($15,000 to $75,000) for this. You can read more about this [here](https://www.theregister.com/2019/02/11/google_gmail_developer/).
 
-OAuth for Yandex is supported via the quick setup wizard.
+OAuth for Yandex and Yahoo is supported via the quick setup wizard.
 
 OAuth for Office 365 accounts is supported, but Microsoft does not offer OAuth for Outlook, Live and Hotmail accounts (yet?).
 
-OAuth access for Yahoo was requested, but Yahoo never responded to the request. OAuth for AOL [was deactivated](https://www.programmableweb.com/api/aol-open-auth) by AOL. Verizon owns both AOL and Yahoo, collectively named [Oath inc](https://en.wikipedia.org/wiki/Verizon_Media). So, it is reasonable to assume that OAuth is not supported by Yahoo anymore too.
-
 <br />
 
 <a name="faq112"></a>
@@ -2302,8 +2301,6 @@ FairEmail groups messages based on the standard *Message-ID*, *In-Reply-To* and
 
 When FairEmail cannot connect to an email server to receive messages, for example when the internet connection is bad or a firewall or a VPN is blocking the connection, FairEmail will wait 8, 16 and 32 seconds while keeping the device awake (=use battery power) and try again to connect. If this fails, FairEmail will schedule an alarm to retry after 15, 30 and 60 minutes and let the device sleep (=no battery usage).
 
-Between connectivity changes there is a wait of 90 seconds to give the email server the opportunity to discover the old connection is broken. This is necessary because the internet connection of a mobile device is often lost abruptly and to prevent the problem described in [this FAQ](#user-content-faq23).
-
 Note that [Android doze mode](https://developer.android.com/training/monitoring-device-state/doze-standby) does not allow to wake the device earlier than after 15 minutes.
 
 *Force sync* in the three-dots menu of the unified inbox can be used to let FairEmail attempt to reconnect without waiting.
@@ -2777,6 +2774,8 @@ Updating once a week will probably be sufficient, please see [here](https://gith
 
 Permanent deletion means that messages will *irreversibly* be lost, and to prevent this from happening accidentally, this always needs to be confirmed. Even with a confirmation, some very angry people who lost some of their messages through their own fault contacted me, which was a rather unpleasant experience :-(
 
+Advanced: the IMAP delete flag in combination with the EXPUNGE command is not supportable because both email servers and not all people can handle this, risking unexpected loss of messages. A complicating factor is that not all email servers support [UID EXPUNGE](https://tools.ietf.org/html/rfc4315).
+
 <br />
 
 <a name="faq161"></a>
diff --git a/docs/FAQ-az-rAZ.md b/docs/FAQ-az-rAZ.md
index 69d6637663..3e4cf02142 100644
--- a/docs/FAQ-az-rAZ.md
+++ b/docs/FAQ-az-rAZ.md
@@ -78,6 +78,7 @@ Related questions:
 * A preview of a message text doesn't (always) appear on Samsung watches because [setLocalOnly](https://developer.android.com/reference/androidx/core/app/NotificationCompat.Builder.html#setLocalOnly(boolean)) seem to be ignored. Message preview texts are known to be displayed correctly on Pebble 2, Fitbit Charge 3, Mi band 3, and Xiaomi Amazfit BIP wearables. See also [this FAQ](#user-content-faq126).
 * A [bug in Android 6.0](https://issuetracker.google.com/issues/37068143) causes a crash with *... Invalid offset: ... Valid range is ...* when text is selected and tapping outside of the selected text. This bug has been fixed in Android 6.0.1.
 * Internal (anchor) links will not work because original messages are shown in an embedded WebView in a scrolling view (the conversation list). This is an Android limitation which cannot be fixed or worked around.
+* Language detection [is not working anymore](https://issuetracker.google.com/issues/173337263) on Pixel devices with (upgraded to?) Android 11
 
 ## Planned features
 
@@ -861,7 +862,7 @@ The error *... Connection refused ...* means that the email server or something
 
 The error *... Network unreachable ...* means that the email server was not reachable via the current internet connection, for example because internet traffic is restricted to local traffic only.
 
-The error *... Host is unresolved ...* or "*... Unable to resolve host ...* means that the address of the email server could not be resolved. This might be caused by ad blocking or an unreachable or not properly working [DNS](https://en.wikipedia.org/wiki/Domain_Name_System) server.
+The error *... Host is unresolved ...*, *... Unable to resolve host ...* or *... No address associated with hostname ...* means that the address of the email server could not be resolved into an IP address. This might be caused by a VPN, ad blocking or an unreachable or not properly working (local) [DNS](https://en.wikipedia.org/wiki/Domain_Name_System) server.
 
 The error *... Software caused connection abort ...* means that the email server or something between FairEmail and the email server actively terminated an existing connection. This can for example happen when connectivity was abruptly lost. A typical example is turning on flight mode.
 
@@ -2162,14 +2163,12 @@ Disabling *Partial fetch* will result in more memory usage.
 <a name="faq111"></a>
 **(111) Is OAuth supported?**
 
-OAuth for Gmail is supported via the quick setup wizard. The Android account manager will be used to fetch and refresh OAuth tokens for selected on-device accounts. OAuth for non on-device accounts is not supported because Google requires a [yearly security audit](https://support.google.com/cloud/answer/9110914) ($15,000 to $75,000) for this.
+OAuth for Gmail is supported via the quick setup wizard. The Android account manager will be used to fetch and refresh OAuth tokens for selected on-device accounts. OAuth for non on-device accounts is not supported because Google requires a [yearly security audit](https://support.google.com/cloud/answer/9110914) ($15,000 to $75,000) for this. You can read more about this [here](https://www.theregister.com/2019/02/11/google_gmail_developer/).
 
-OAuth for Yandex is supported via the quick setup wizard.
+OAuth for Yandex and Yahoo is supported via the quick setup wizard.
 
 OAuth for Office 365 accounts is supported, but Microsoft does not offer OAuth for Outlook, Live and Hotmail accounts (yet?).
 
-OAuth access for Yahoo was requested, but Yahoo never responded to the request. OAuth for AOL [was deactivated](https://www.programmableweb.com/api/aol-open-auth) by AOL. Verizon owns both AOL and Yahoo, collectively named [Oath inc](https://en.wikipedia.org/wiki/Verizon_Media). So, it is reasonable to assume that OAuth is not supported by Yahoo anymore too.
-
 <br />
 
 <a name="faq112"></a>
@@ -2302,8 +2301,6 @@ FairEmail groups messages based on the standard *Message-ID*, *In-Reply-To* and
 
 When FairEmail cannot connect to an email server to receive messages, for example when the internet connection is bad or a firewall or a VPN is blocking the connection, FairEmail will wait 8, 16 and 32 seconds while keeping the device awake (=use battery power) and try again to connect. If this fails, FairEmail will schedule an alarm to retry after 15, 30 and 60 minutes and let the device sleep (=no battery usage).
 
-Between connectivity changes there is a wait of 90 seconds to give the email server the opportunity to discover the old connection is broken. This is necessary because the internet connection of a mobile device is often lost abruptly and to prevent the problem described in [this FAQ](#user-content-faq23).
-
 Note that [Android doze mode](https://developer.android.com/training/monitoring-device-state/doze-standby) does not allow to wake the device earlier than after 15 minutes.
 
 *Force sync* in the three-dots menu of the unified inbox can be used to let FairEmail attempt to reconnect without waiting.
@@ -2777,6 +2774,8 @@ Updating once a week will probably be sufficient, please see [here](https://gith
 
 Permanent deletion means that messages will *irreversibly* be lost, and to prevent this from happening accidentally, this always needs to be confirmed. Even with a confirmation, some very angry people who lost some of their messages through their own fault contacted me, which was a rather unpleasant experience :-(
 
+Advanced: the IMAP delete flag in combination with the EXPUNGE command is not supportable because both email servers and not all people can handle this, risking unexpected loss of messages. A complicating factor is that not all email servers support [UID EXPUNGE](https://tools.ietf.org/html/rfc4315).
+
 <br />
 
 <a name="faq161"></a>
diff --git a/docs/FAQ-bg-rBG.md b/docs/FAQ-bg-rBG.md
index 7b7b451250..a593607a58 100644
--- a/docs/FAQ-bg-rBG.md
+++ b/docs/FAQ-bg-rBG.md
@@ -78,6 +78,7 @@ Related questions:
 * A preview of a message text doesn't (always) appear on Samsung watches because [setLocalOnly](https://developer.android.com/reference/androidx/core/app/NotificationCompat.Builder.html#setLocalOnly(boolean)) seem to be ignored. Message preview texts are known to be displayed correctly on Pebble 2, Fitbit Charge 3, Mi band 3, and Xiaomi Amazfit BIP wearables. See also [this FAQ](#user-content-faq126).
 * A [bug in Android 6.0](https://issuetracker.google.com/issues/37068143) causes a crash with *... Invalid offset: ... Valid range is ...* when text is selected and tapping outside of the selected text. This bug has been fixed in Android 6.0.1.
 * Internal (anchor) links will not work because original messages are shown in an embedded WebView in a scrolling view (the conversation list). This is an Android limitation which cannot be fixed or worked around.
+* Language detection [is not working anymore](https://issuetracker.google.com/issues/173337263) on Pixel devices with (upgraded to?) Android 11
 
 ## Planned features
 
@@ -861,7 +862,7 @@ The error *... Connection refused ...* means that the email server or something
 
 The error *... Network unreachable ...* means that the email server was not reachable via the current internet connection, for example because internet traffic is restricted to local traffic only.
 
-The error *... Host is unresolved ...* or "*... Unable to resolve host ...* means that the address of the email server could not be resolved. This might be caused by ad blocking or an unreachable or not properly working [DNS](https://en.wikipedia.org/wiki/Domain_Name_System) server.
+The error *... Host is unresolved ...*, *... Unable to resolve host ...* or *... No address associated with hostname ...* means that the address of the email server could not be resolved into an IP address. This might be caused by a VPN, ad blocking or an unreachable or not properly working (local) [DNS](https://en.wikipedia.org/wiki/Domain_Name_System) server.
 
 The error *... Software caused connection abort ...* means that the email server or something between FairEmail and the email server actively terminated an existing connection. This can for example happen when connectivity was abruptly lost. A typical example is turning on flight mode.
 
@@ -2162,14 +2163,12 @@ Disabling *Partial fetch* will result in more memory usage.
 <a name="faq111"></a>
 **(111) Is OAuth supported?**
 
-OAuth for Gmail is supported via the quick setup wizard. The Android account manager will be used to fetch and refresh OAuth tokens for selected on-device accounts. OAuth for non on-device accounts is not supported because Google requires a [yearly security audit](https://support.google.com/cloud/answer/9110914) ($15,000 to $75,000) for this.
+OAuth for Gmail is supported via the quick setup wizard. The Android account manager will be used to fetch and refresh OAuth tokens for selected on-device accounts. OAuth for non on-device accounts is not supported because Google requires a [yearly security audit](https://support.google.com/cloud/answer/9110914) ($15,000 to $75,000) for this. You can read more about this [here](https://www.theregister.com/2019/02/11/google_gmail_developer/).
 
-OAuth for Yandex is supported via the quick setup wizard.
+OAuth for Yandex and Yahoo is supported via the quick setup wizard.
 
 OAuth for Office 365 accounts is supported, but Microsoft does not offer OAuth for Outlook, Live and Hotmail accounts (yet?).
 
-OAuth access for Yahoo was requested, but Yahoo never responded to the request. OAuth for AOL [was deactivated](https://www.programmableweb.com/api/aol-open-auth) by AOL. Verizon owns both AOL and Yahoo, collectively named [Oath inc](https://en.wikipedia.org/wiki/Verizon_Media). So, it is reasonable to assume that OAuth is not supported by Yahoo anymore too.
-
 <br />
 
 <a name="faq112"></a>
@@ -2302,8 +2301,6 @@ FairEmail groups messages based on the standard *Message-ID*, *In-Reply-To* and
 
 When FairEmail cannot connect to an email server to receive messages, for example when the internet connection is bad or a firewall or a VPN is blocking the connection, FairEmail will wait 8, 16 and 32 seconds while keeping the device awake (=use battery power) and try again to connect. If this fails, FairEmail will schedule an alarm to retry after 15, 30 and 60 minutes and let the device sleep (=no battery usage).
 
-Between connectivity changes there is a wait of 90 seconds to give the email server the opportunity to discover the old connection is broken. This is necessary because the internet connection of a mobile device is often lost abruptly and to prevent the problem described in [this FAQ](#user-content-faq23).
-
 Note that [Android doze mode](https://developer.android.com/training/monitoring-device-state/doze-standby) does not allow to wake the device earlier than after 15 minutes.
 
 *Force sync* in the three-dots menu of the unified inbox can be used to let FairEmail attempt to reconnect without waiting.
@@ -2777,6 +2774,8 @@ Updating once a week will probably be sufficient, please see [here](https://gith
 
 Permanent deletion means that messages will *irreversibly* be lost, and to prevent this from happening accidentally, this always needs to be confirmed. Even with a confirmation, some very angry people who lost some of their messages through their own fault contacted me, which was a rather unpleasant experience :-(
 
+Advanced: the IMAP delete flag in combination with the EXPUNGE command is not supportable because both email servers and not all people can handle this, risking unexpected loss of messages. A complicating factor is that not all email servers support [UID EXPUNGE](https://tools.ietf.org/html/rfc4315).
+
 <br />
 
 <a name="faq161"></a>
diff --git a/docs/FAQ-bn-rBD.md b/docs/FAQ-bn-rBD.md
index 7b7b451250..a593607a58 100644
--- a/docs/FAQ-bn-rBD.md
+++ b/docs/FAQ-bn-rBD.md
@@ -78,6 +78,7 @@ Related questions:
 * A preview of a message text doesn't (always) appear on Samsung watches because [setLocalOnly](https://developer.android.com/reference/androidx/core/app/NotificationCompat.Builder.html#setLocalOnly(boolean)) seem to be ignored. Message preview texts are known to be displayed correctly on Pebble 2, Fitbit Charge 3, Mi band 3, and Xiaomi Amazfit BIP wearables. See also [this FAQ](#user-content-faq126).
 * A [bug in Android 6.0](https://issuetracker.google.com/issues/37068143) causes a crash with *... Invalid offset: ... Valid range is ...* when text is selected and tapping outside of the selected text. This bug has been fixed in Android 6.0.1.
 * Internal (anchor) links will not work because original messages are shown in an embedded WebView in a scrolling view (the conversation list). This is an Android limitation which cannot be fixed or worked around.
+* Language detection [is not working anymore](https://issuetracker.google.com/issues/173337263) on Pixel devices with (upgraded to?) Android 11
 
 ## Planned features
 
@@ -861,7 +862,7 @@ The error *... Connection refused ...* means that the email server or something
 
 The error *... Network unreachable ...* means that the email server was not reachable via the current internet connection, for example because internet traffic is restricted to local traffic only.
 
-The error *... Host is unresolved ...* or "*... Unable to resolve host ...* means that the address of the email server could not be resolved. This might be caused by ad blocking or an unreachable or not properly working [DNS](https://en.wikipedia.org/wiki/Domain_Name_System) server.
+The error *... Host is unresolved ...*, *... Unable to resolve host ...* or *... No address associated with hostname ...* means that the address of the email server could not be resolved into an IP address. This might be caused by a VPN, ad blocking or an unreachable or not properly working (local) [DNS](https://en.wikipedia.org/wiki/Domain_Name_System) server.
 
 The error *... Software caused connection abort ...* means that the email server or something between FairEmail and the email server actively terminated an existing connection. This can for example happen when connectivity was abruptly lost. A typical example is turning on flight mode.
 
@@ -2162,14 +2163,12 @@ Disabling *Partial fetch* will result in more memory usage.
 <a name="faq111"></a>
 **(111) Is OAuth supported?**
 
-OAuth for Gmail is supported via the quick setup wizard. The Android account manager will be used to fetch and refresh OAuth tokens for selected on-device accounts. OAuth for non on-device accounts is not supported because Google requires a [yearly security audit](https://support.google.com/cloud/answer/9110914) ($15,000 to $75,000) for this.
+OAuth for Gmail is supported via the quick setup wizard. The Android account manager will be used to fetch and refresh OAuth tokens for selected on-device accounts. OAuth for non on-device accounts is not supported because Google requires a [yearly security audit](https://support.google.com/cloud/answer/9110914) ($15,000 to $75,000) for this. You can read more about this [here](https://www.theregister.com/2019/02/11/google_gmail_developer/).
 
-OAuth for Yandex is supported via the quick setup wizard.
+OAuth for Yandex and Yahoo is supported via the quick setup wizard.
 
 OAuth for Office 365 accounts is supported, but Microsoft does not offer OAuth for Outlook, Live and Hotmail accounts (yet?).
 
-OAuth access for Yahoo was requested, but Yahoo never responded to the request. OAuth for AOL [was deactivated](https://www.programmableweb.com/api/aol-open-auth) by AOL. Verizon owns both AOL and Yahoo, collectively named [Oath inc](https://en.wikipedia.org/wiki/Verizon_Media). So, it is reasonable to assume that OAuth is not supported by Yahoo anymore too.
-
 <br />
 
 <a name="faq112"></a>
@@ -2302,8 +2301,6 @@ FairEmail groups messages based on the standard *Message-ID*, *In-Reply-To* and
 
 When FairEmail cannot connect to an email server to receive messages, for example when the internet connection is bad or a firewall or a VPN is blocking the connection, FairEmail will wait 8, 16 and 32 seconds while keeping the device awake (=use battery power) and try again to connect. If this fails, FairEmail will schedule an alarm to retry after 15, 30 and 60 minutes and let the device sleep (=no battery usage).
 
-Between connectivity changes there is a wait of 90 seconds to give the email server the opportunity to discover the old connection is broken. This is necessary because the internet connection of a mobile device is often lost abruptly and to prevent the problem described in [this FAQ](#user-content-faq23).
-
 Note that [Android doze mode](https://developer.android.com/training/monitoring-device-state/doze-standby) does not allow to wake the device earlier than after 15 minutes.
 
 *Force sync* in the three-dots menu of the unified inbox can be used to let FairEmail attempt to reconnect without waiting.
@@ -2777,6 +2774,8 @@ Updating once a week will probably be sufficient, please see [here](https://gith
 
 Permanent deletion means that messages will *irreversibly* be lost, and to prevent this from happening accidentally, this always needs to be confirmed. Even with a confirmation, some very angry people who lost some of their messages through their own fault contacted me, which was a rather unpleasant experience :-(
 
+Advanced: the IMAP delete flag in combination with the EXPUNGE command is not supportable because both email servers and not all people can handle this, risking unexpected loss of messages. A complicating factor is that not all email servers support [UID EXPUNGE](https://tools.ietf.org/html/rfc4315).
+
 <br />
 
 <a name="faq161"></a>
diff --git a/docs/FAQ-bn-rIN.md b/docs/FAQ-bn-rIN.md
index 7b7b451250..a593607a58 100644
--- a/docs/FAQ-bn-rIN.md
+++ b/docs/FAQ-bn-rIN.md
@@ -78,6 +78,7 @@ Related questions:
 * A preview of a message text doesn't (always) appear on Samsung watches because [setLocalOnly](https://developer.android.com/reference/androidx/core/app/NotificationCompat.Builder.html#setLocalOnly(boolean)) seem to be ignored. Message preview texts are known to be displayed correctly on Pebble 2, Fitbit Charge 3, Mi band 3, and Xiaomi Amazfit BIP wearables. See also [this FAQ](#user-content-faq126).
 * A [bug in Android 6.0](https://issuetracker.google.com/issues/37068143) causes a crash with *... Invalid offset: ... Valid range is ...* when text is selected and tapping outside of the selected text. This bug has been fixed in Android 6.0.1.
 * Internal (anchor) links will not work because original messages are shown in an embedded WebView in a scrolling view (the conversation list). This is an Android limitation which cannot be fixed or worked around.
+* Language detection [is not working anymore](https://issuetracker.google.com/issues/173337263) on Pixel devices with (upgraded to?) Android 11
 
 ## Planned features
 
@@ -861,7 +862,7 @@ The error *... Connection refused ...* means that the email server or something
 
 The error *... Network unreachable ...* means that the email server was not reachable via the current internet connection, for example because internet traffic is restricted to local traffic only.
 
-The error *... Host is unresolved ...* or "*... Unable to resolve host ...* means that the address of the email server could not be resolved. This might be caused by ad blocking or an unreachable or not properly working [DNS](https://en.wikipedia.org/wiki/Domain_Name_System) server.
+The error *... Host is unresolved ...*, *... Unable to resolve host ...* or *... No address associated with hostname ...* means that the address of the email server could not be resolved into an IP address. This might be caused by a VPN, ad blocking or an unreachable or not properly working (local) [DNS](https://en.wikipedia.org/wiki/Domain_Name_System) server.
 
 The error *... Software caused connection abort ...* means that the email server or something between FairEmail and the email server actively terminated an existing connection. This can for example happen when connectivity was abruptly lost. A typical example is turning on flight mode.
 
@@ -2162,14 +2163,12 @@ Disabling *Partial fetch* will result in more memory usage.
 <a name="faq111"></a>
 **(111) Is OAuth supported?**
 
-OAuth for Gmail is supported via the quick setup wizard. The Android account manager will be used to fetch and refresh OAuth tokens for selected on-device accounts. OAuth for non on-device accounts is not supported because Google requires a [yearly security audit](https://support.google.com/cloud/answer/9110914) ($15,000 to $75,000) for this.
+OAuth for Gmail is supported via the quick setup wizard. The Android account manager will be used to fetch and refresh OAuth tokens for selected on-device accounts. OAuth for non on-device accounts is not supported because Google requires a [yearly security audit](https://support.google.com/cloud/answer/9110914) ($15,000 to $75,000) for this. You can read more about this [here](https://www.theregister.com/2019/02/11/google_gmail_developer/).
 
-OAuth for Yandex is supported via the quick setup wizard.
+OAuth for Yandex and Yahoo is supported via the quick setup wizard.
 
 OAuth for Office 365 accounts is supported, but Microsoft does not offer OAuth for Outlook, Live and Hotmail accounts (yet?).
 
-OAuth access for Yahoo was requested, but Yahoo never responded to the request. OAuth for AOL [was deactivated](https://www.programmableweb.com/api/aol-open-auth) by AOL. Verizon owns both AOL and Yahoo, collectively named [Oath inc](https://en.wikipedia.org/wiki/Verizon_Media). So, it is reasonable to assume that OAuth is not supported by Yahoo anymore too.
-
 <br />
 
 <a name="faq112"></a>
@@ -2302,8 +2301,6 @@ FairEmail groups messages based on the standard *Message-ID*, *In-Reply-To* and
 
 When FairEmail cannot connect to an email server to receive messages, for example when the internet connection is bad or a firewall or a VPN is blocking the connection, FairEmail will wait 8, 16 and 32 seconds while keeping the device awake (=use battery power) and try again to connect. If this fails, FairEmail will schedule an alarm to retry after 15, 30 and 60 minutes and let the device sleep (=no battery usage).
 
-Between connectivity changes there is a wait of 90 seconds to give the email server the opportunity to discover the old connection is broken. This is necessary because the internet connection of a mobile device is often lost abruptly and to prevent the problem described in [this FAQ](#user-content-faq23).
-
 Note that [Android doze mode](https://developer.android.com/training/monitoring-device-state/doze-standby) does not allow to wake the device earlier than after 15 minutes.
 
 *Force sync* in the three-dots menu of the unified inbox can be used to let FairEmail attempt to reconnect without waiting.
@@ -2777,6 +2774,8 @@ Updating once a week will probably be sufficient, please see [here](https://gith
 
 Permanent deletion means that messages will *irreversibly* be lost, and to prevent this from happening accidentally, this always needs to be confirmed. Even with a confirmation, some very angry people who lost some of their messages through their own fault contacted me, which was a rather unpleasant experience :-(
 
+Advanced: the IMAP delete flag in combination with the EXPUNGE command is not supportable because both email servers and not all people can handle this, risking unexpected loss of messages. A complicating factor is that not all email servers support [UID EXPUNGE](https://tools.ietf.org/html/rfc4315).
+
 <br />
 
 <a name="faq161"></a>
diff --git a/docs/FAQ-ca-rES.md b/docs/FAQ-ca-rES.md
index 7b7b451250..a593607a58 100644
--- a/docs/FAQ-ca-rES.md
+++ b/docs/FAQ-ca-rES.md
@@ -78,6 +78,7 @@ Related questions:
 * A preview of a message text doesn't (always) appear on Samsung watches because [setLocalOnly](https://developer.android.com/reference/androidx/core/app/NotificationCompat.Builder.html#setLocalOnly(boolean)) seem to be ignored. Message preview texts are known to be displayed correctly on Pebble 2, Fitbit Charge 3, Mi band 3, and Xiaomi Amazfit BIP wearables. See also [this FAQ](#user-content-faq126).
 * A [bug in Android 6.0](https://issuetracker.google.com/issues/37068143) causes a crash with *... Invalid offset: ... Valid range is ...* when text is selected and tapping outside of the selected text. This bug has been fixed in Android 6.0.1.
 * Internal (anchor) links will not work because original messages are shown in an embedded WebView in a scrolling view (the conversation list). This is an Android limitation which cannot be fixed or worked around.
+* Language detection [is not working anymore](https://issuetracker.google.com/issues/173337263) on Pixel devices with (upgraded to?) Android 11
 
 ## Planned features
 
@@ -861,7 +862,7 @@ The error *... Connection refused ...* means that the email server or something
 
 The error *... Network unreachable ...* means that the email server was not reachable via the current internet connection, for example because internet traffic is restricted to local traffic only.
 
-The error *... Host is unresolved ...* or "*... Unable to resolve host ...* means that the address of the email server could not be resolved. This might be caused by ad blocking or an unreachable or not properly working [DNS](https://en.wikipedia.org/wiki/Domain_Name_System) server.
+The error *... Host is unresolved ...*, *... Unable to resolve host ...* or *... No address associated with hostname ...* means that the address of the email server could not be resolved into an IP address. This might be caused by a VPN, ad blocking or an unreachable or not properly working (local) [DNS](https://en.wikipedia.org/wiki/Domain_Name_System) server.
 
 The error *... Software caused connection abort ...* means that the email server or something between FairEmail and the email server actively terminated an existing connection. This can for example happen when connectivity was abruptly lost. A typical example is turning on flight mode.
 
@@ -2162,14 +2163,12 @@ Disabling *Partial fetch* will result in more memory usage.
 <a name="faq111"></a>
 **(111) Is OAuth supported?**
 
-OAuth for Gmail is supported via the quick setup wizard. The Android account manager will be used to fetch and refresh OAuth tokens for selected on-device accounts. OAuth for non on-device accounts is not supported because Google requires a [yearly security audit](https://support.google.com/cloud/answer/9110914) ($15,000 to $75,000) for this.
+OAuth for Gmail is supported via the quick setup wizard. The Android account manager will be used to fetch and refresh OAuth tokens for selected on-device accounts. OAuth for non on-device accounts is not supported because Google requires a [yearly security audit](https://support.google.com/cloud/answer/9110914) ($15,000 to $75,000) for this. You can read more about this [here](https://www.theregister.com/2019/02/11/google_gmail_developer/).
 
-OAuth for Yandex is supported via the quick setup wizard.
+OAuth for Yandex and Yahoo is supported via the quick setup wizard.
 
 OAuth for Office 365 accounts is supported, but Microsoft does not offer OAuth for Outlook, Live and Hotmail accounts (yet?).
 
-OAuth access for Yahoo was requested, but Yahoo never responded to the request. OAuth for AOL [was deactivated](https://www.programmableweb.com/api/aol-open-auth) by AOL. Verizon owns both AOL and Yahoo, collectively named [Oath inc](https://en.wikipedia.org/wiki/Verizon_Media). So, it is reasonable to assume that OAuth is not supported by Yahoo anymore too.
-
 <br />
 
 <a name="faq112"></a>
@@ -2302,8 +2301,6 @@ FairEmail groups messages based on the standard *Message-ID*, *In-Reply-To* and
 
 When FairEmail cannot connect to an email server to receive messages, for example when the internet connection is bad or a firewall or a VPN is blocking the connection, FairEmail will wait 8, 16 and 32 seconds while keeping the device awake (=use battery power) and try again to connect. If this fails, FairEmail will schedule an alarm to retry after 15, 30 and 60 minutes and let the device sleep (=no battery usage).
 
-Between connectivity changes there is a wait of 90 seconds to give the email server the opportunity to discover the old connection is broken. This is necessary because the internet connection of a mobile device is often lost abruptly and to prevent the problem described in [this FAQ](#user-content-faq23).
-
 Note that [Android doze mode](https://developer.android.com/training/monitoring-device-state/doze-standby) does not allow to wake the device earlier than after 15 minutes.
 
 *Force sync* in the three-dots menu of the unified inbox can be used to let FairEmail attempt to reconnect without waiting.
@@ -2777,6 +2774,8 @@ Updating once a week will probably be sufficient, please see [here](https://gith
 
 Permanent deletion means that messages will *irreversibly* be lost, and to prevent this from happening accidentally, this always needs to be confirmed. Even with a confirmation, some very angry people who lost some of their messages through their own fault contacted me, which was a rather unpleasant experience :-(
 
+Advanced: the IMAP delete flag in combination with the EXPUNGE command is not supportable because both email servers and not all people can handle this, risking unexpected loss of messages. A complicating factor is that not all email servers support [UID EXPUNGE](https://tools.ietf.org/html/rfc4315).
+
 <br />
 
 <a name="faq161"></a>
diff --git a/docs/FAQ-cs-rCZ.md b/docs/FAQ-cs-rCZ.md
index 7a22e0ae31..e007df1b94 100644
--- a/docs/FAQ-cs-rCZ.md
+++ b/docs/FAQ-cs-rCZ.md
@@ -78,6 +78,7 @@ Související dotazy:
 * Náhled textu zprávy se na Samsung hodinkách někdy (nikdy) nezobrazí, protože [setLocalOnly](https://developer.android.com/reference/androidx/core/app/NotificationCompat.Builder.html#setLocalOnly(boolean)) se zdá být ignorován. Message preview texts are known to be displayed correctly on Pebble 2, Fitbit Charge 3, Mi band 3, and Xiaomi Amazfit BIP wearables. Viz také [tento nejčastější dotaz](#user-content-faq126).
 * A [bug in Android 6.0](https://issuetracker.google.com/issues/37068143) causes a crash with *... Invalid offset: ... Valid range is ...* when text is selected and tapping outside of the selected text. This bug has been fixed in Android 6.0.1.
 * Internal (anchor) links will not work because original messages are shown in an embedded WebView in a scrolling view (the conversation list). This is an Android limitation which cannot be fixed or worked around.
+* Language detection [is not working anymore](https://issuetracker.google.com/issues/173337263) on Pixel devices with (upgraded to?) Android 11
 
 ## Plánované funkce
 
@@ -861,7 +862,7 @@ The error *... Connection refused ...* means that the email server or something
 
 The error *... Network unreachable ...* means that the email server was not reachable via the current internet connection, for example because internet traffic is restricted to local traffic only.
 
-The error *... Host is unresolved ...* or "*... Unable to resolve host ...* means that the address of the email server could not be resolved. This might be caused by ad blocking or an unreachable or not properly working [DNS](https://en.wikipedia.org/wiki/Domain_Name_System) server.
+The error *... Host is unresolved ...*, *... Unable to resolve host ...* or *... No address associated with hostname ...* means that the address of the email server could not be resolved into an IP address. This might be caused by a VPN, ad blocking or an unreachable or not properly working (local) [DNS](https://en.wikipedia.org/wiki/Domain_Name_System) server.
 
 The error *... Software caused connection abort ...* means that the email server or something between FairEmail and the email server actively terminated an existing connection. This can for example happen when connectivity was abruptly lost. A typical example is turning on flight mode.
 
@@ -2162,14 +2163,12 @@ Disabling *Partial fetch* will result in more memory usage.
 <a name="faq111"></a>
 **(111) Is OAuth supported?**
 
-OAuth for Gmail is supported via the quick setup wizard. The Android account manager will be used to fetch and refresh OAuth tokens for selected on-device accounts. OAuth for non on-device accounts is not supported because Google requires a [yearly security audit](https://support.google.com/cloud/answer/9110914) ($15,000 to $75,000) for this.
+OAuth for Gmail is supported via the quick setup wizard. The Android account manager will be used to fetch and refresh OAuth tokens for selected on-device accounts. OAuth for non on-device accounts is not supported because Google requires a [yearly security audit](https://support.google.com/cloud/answer/9110914) ($15,000 to $75,000) for this. You can read more about this [here](https://www.theregister.com/2019/02/11/google_gmail_developer/).
 
-OAuth for Yandex is supported via the quick setup wizard.
+OAuth for Yandex and Yahoo is supported via the quick setup wizard.
 
 OAuth for Office 365 accounts is supported, but Microsoft does not offer OAuth for Outlook, Live and Hotmail accounts (yet?).
 
-OAuth access for Yahoo was requested, but Yahoo never responded to the request. OAuth for AOL [was deactivated](https://www.programmableweb.com/api/aol-open-auth) by AOL. Verizon owns both AOL and Yahoo, collectively named [Oath inc](https://en.wikipedia.org/wiki/Verizon_Media). So, it is reasonable to assume that OAuth is not supported by Yahoo anymore too.
-
 <br />
 
 <a name="faq112"></a>
@@ -2302,8 +2301,6 @@ FairEmail groups messages based on the standard *Message-ID*, *In-Reply-To* and
 
 When FairEmail cannot connect to an email server to receive messages, for example when the internet connection is bad or a firewall or a VPN is blocking the connection, FairEmail will wait 8, 16 and 32 seconds while keeping the device awake (=use battery power) and try again to connect. If this fails, FairEmail will schedule an alarm to retry after 15, 30 and 60 minutes and let the device sleep (=no battery usage).
 
-Between connectivity changes there is a wait of 90 seconds to give the email server the opportunity to discover the old connection is broken. This is necessary because the internet connection of a mobile device is often lost abruptly and to prevent the problem described in [this FAQ](#user-content-faq23).
-
 Note that [Android doze mode](https://developer.android.com/training/monitoring-device-state/doze-standby) does not allow to wake the device earlier than after 15 minutes.
 
 *Force sync* in the three-dots menu of the unified inbox can be used to let FairEmail attempt to reconnect without waiting.
@@ -2777,6 +2774,8 @@ Updating once a week will probably be sufficient, please see [here](https://gith
 
 Permanent deletion means that messages will *irreversibly* be lost, and to prevent this from happening accidentally, this always needs to be confirmed. Even with a confirmation, some very angry people who lost some of their messages through their own fault contacted me, which was a rather unpleasant experience :-(
 
+Advanced: the IMAP delete flag in combination with the EXPUNGE command is not supportable because both email servers and not all people can handle this, risking unexpected loss of messages. A complicating factor is that not all email servers support [UID EXPUNGE](https://tools.ietf.org/html/rfc4315).
+
 <br />
 
 <a name="faq161"></a>
diff --git a/docs/FAQ-da-rDK.md b/docs/FAQ-da-rDK.md
index 91e8630f0f..1aca71740a 100644
--- a/docs/FAQ-da-rDK.md
+++ b/docs/FAQ-da-rDK.md
@@ -78,6 +78,7 @@ Relaterede spørgsmål:
 * En forhåndsvisning af en beskedtekst vises ikke (altid) på Samsung-ure, da [setLocalOnly](https://developer.android.com/reference/androidx/core/app/NotificationCompat.Builder.html#setLocalOnly(boolean))-parameteren synes at blive ignoreret. Beskedforhåndsvisningstekster fremgår korrekt på Pebble 2-, Fitbit Charge 3- og Mi band 3-wearables. Se også [denne FAQ](#user-content-faq126).
 * En [fejl i Android](https://issuetracker.google.com/issues/37068143) medfører af og til et nedbrud med "*... Ugyldig forskydning... Gyldigt område er ...* når tekst er valgt og der trykkes uden for den valgte tekst. Denne fejl er rettet i Android 6.0.1.
 * Interne (anker-) links vil ikke fungere, da de oprindelige beskeder vises i et indlejret WebView i en rullevisning (samtalelisten). Dette er en Android-begrænsning, der ikke kan rettes eller omgås.
+* Language detection [is not working anymore](https://issuetracker.google.com/issues/173337263) on Pixel devices with (upgraded to?) Android 11
 
 ## Planlagte funktioner
 
@@ -861,7 +862,7 @@ Fejlen *... Forbindelse nægtet ...* betyder, at e-mailserveren eller noget mell
 
 Fejlen *... Netværk utilgængeligt ...* betyder, at e-mailserveren ikke kunne nås via den aktuelle Internetforbindelse, f.eks. fordi Internettrafik er begrænset til alene lokal trafik.
 
-Fejlen *... Vært er uopløst ...* eller "*... Kan ikke opløse vært ...* betyder, at e-mailserverens værtsadressen ikke kunne opløses. Dette kan forårsages af en adblocker, eller en utilgængelig eller ikke korrekt fungerende [DNS-server](https://en.wikipedia.org/wiki/Domain_Name_System).
+Fejlen *... Host is unresolved ...*, *... Unable to resolve host ...* or *... No address associated with hostname ...* means that the address of the email server could not be resolved into an IP address. This might be caused by a VPN, ad blocking or an unreachable or not properly working (local) [DNS](https://en.wikipedia.org/wiki/Domain_Name_System) server.
 
 Fejlen *... Software forårsagede forbindelsesafbrydelse ...* betyder, at e-mailserveren, eller noget mellem FairEmail og e-mailserveren, aktivt afsluttede en eksisterende forbindelse. Dette kan f.eks. ske, hvis tilslutningen pludselig blev mistet. Et typisk eksempel er aktivering af Flytilstand.
 
@@ -2162,14 +2163,12 @@ Disabling *Partial fetch* will result in more memory usage.
 <a name="faq111"></a>
 **(111) Is OAuth supported?**
 
-OAuth for Gmail is supported via the quick setup wizard. The Android account manager will be used to fetch and refresh OAuth tokens for selected on-device accounts. OAuth for non on-device accounts is not supported because Google requires a [yearly security audit](https://support.google.com/cloud/answer/9110914) ($15,000 to $75,000) for this.
+OAuth for Gmail is supported via the quick setup wizard. The Android account manager will be used to fetch and refresh OAuth tokens for selected on-device accounts. OAuth for non on-device accounts is not supported because Google requires a [yearly security audit](https://support.google.com/cloud/answer/9110914) ($15,000 to $75,000) for this. You can read more about this [here](https://www.theregister.com/2019/02/11/google_gmail_developer/).
 
-OAuth for Yandex is supported via the quick setup wizard.
+OAuth for Yandex and Yahoo is supported via the quick setup wizard.
 
 OAuth for Office 365 accounts is supported, but Microsoft does not offer OAuth for Outlook, Live and Hotmail accounts (yet?).
 
-OAuth access for Yahoo was requested, but Yahoo never responded to the request. OAuth for AOL [was deactivated](https://www.programmableweb.com/api/aol-open-auth) by AOL. Verizon owns both AOL and Yahoo, collectively named [Oath inc](https://en.wikipedia.org/wiki/Verizon_Media). So, it is reasonable to assume that OAuth is not supported by Yahoo anymore too.
-
 <br />
 
 <a name="faq112"></a>
@@ -2302,8 +2301,6 @@ FairEmail groups messages based on the standard *Message-ID*, *In-Reply-To* and
 
 When FairEmail cannot connect to an email server to receive messages, for example when the internet connection is bad or a firewall or a VPN is blocking the connection, FairEmail will wait 8, 16 and 32 seconds while keeping the device awake (=use battery power) and try again to connect. If this fails, FairEmail will schedule an alarm to retry after 15, 30 and 60 minutes and let the device sleep (=no battery usage).
 
-Between connectivity changes there is a wait of 90 seconds to give the email server the opportunity to discover the old connection is broken. This is necessary because the internet connection of a mobile device is often lost abruptly and to prevent the problem described in [this FAQ](#user-content-faq23).
-
 Note that [Android doze mode](https://developer.android.com/training/monitoring-device-state/doze-standby) does not allow to wake the device earlier than after 15 minutes.
 
 *Force sync* in the three-dots menu of the unified inbox can be used to let FairEmail attempt to reconnect without waiting.
@@ -2777,6 +2774,8 @@ Updating once a week will probably be sufficient, please see [here](https://gith
 
 Permanent deletion means that messages will *irreversibly* be lost, and to prevent this from happening accidentally, this always needs to be confirmed. Even with a confirmation, some very angry people who lost some of their messages through their own fault contacted me, which was a rather unpleasant experience :-(
 
+Advanced: the IMAP delete flag in combination with the EXPUNGE command is not supportable because both email servers and not all people can handle this, risking unexpected loss of messages. A complicating factor is that not all email servers support [UID EXPUNGE](https://tools.ietf.org/html/rfc4315).
+
 <br />
 
 <a name="faq161"></a>
diff --git a/docs/FAQ-de-rAT.md b/docs/FAQ-de-rAT.md
index a0bd0648f0..2b9603de63 100644
--- a/docs/FAQ-de-rAT.md
+++ b/docs/FAQ-de-rAT.md
@@ -78,6 +78,7 @@ Verwandte Fragen:
 * Eine Vorschau eines Nachrichtentextes wird auf Samsung-Uhren nicht (immer) angezeigt, weil [setLocalOnly](https://developer.android.com/reference/androidx/core/app/NotificationCompat.Builder.html#setLocalOnly(boolean)) wohl ignoriert wird. Bisher ist nur bekannt, dass Nachrichtenvorschautexte auf den Smart-Armbändern „Pebble 2”, „Fitbit Charge 3”, „Mi Band 3” und „Xiaomi Amazfit BIP” korrekt angezeigt werden. Siehe auch [diese FAQ](#user-content-faq126).
 * Ein [Fehler in Android 6.0](https://issuetracker.google.com/issues/37068143) verursacht einen Absturz mit * … Ungültiger Offset: ... Der gültige Bereich ist …* wenn Text ausgewählt ist und außerhalb des ausgewählten Textes angetippt wird. Dieser Fehler wurde in Android 6.0.1 behoben.
 * Interne (Anker-)Links funktionieren nicht, da die Originalnachrichten in einer eingebetteten Web-Ansicht in einer scrollenden Ansicht (der Konversationsliste) angezeigt werden. Dies ist eine Einschränkung von Android, die nicht behoben oder umgangen werden kann.
+* Language detection [is not working anymore](https://issuetracker.google.com/issues/173337263) on Pixel devices with (upgraded to?) Android 11
 
 ## Geplante Funktionen
 
@@ -861,7 +862,7 @@ The error *... Connection refused ...* means that the email server or something
 
 The error *... Network unreachable ...* means that the email server was not reachable via the current internet connection, for example because internet traffic is restricted to local traffic only.
 
-The error *... Host is unresolved ...* or "*... Unable to resolve host ...* means that the address of the email server could not be resolved. This might be caused by ad blocking or an unreachable or not properly working [DNS](https://en.wikipedia.org/wiki/Domain_Name_System) server.
+The error *... Host is unresolved ...*, *... Unable to resolve host ...* or *... No address associated with hostname ...* means that the address of the email server could not be resolved into an IP address. This might be caused by a VPN, ad blocking or an unreachable or not properly working (local) [DNS](https://en.wikipedia.org/wiki/Domain_Name_System) server.
 
 The error *... Software caused connection abort ...* means that the email server or something between FairEmail and the email server actively terminated an existing connection. This can for example happen when connectivity was abruptly lost. A typical example is turning on flight mode.
 
@@ -2162,14 +2163,12 @@ Disabling *Partial fetch* will result in more memory usage.
 <a name="faq111"></a>
 **(111) Is OAuth supported?**
 
-OAuth for Gmail is supported via the quick setup wizard. The Android account manager will be used to fetch and refresh OAuth tokens for selected on-device accounts. OAuth for non on-device accounts is not supported because Google requires a [yearly security audit](https://support.google.com/cloud/answer/9110914) ($15,000 to $75,000) for this.
+OAuth for Gmail is supported via the quick setup wizard. The Android account manager will be used to fetch and refresh OAuth tokens for selected on-device accounts. OAuth for non on-device accounts is not supported because Google requires a [yearly security audit](https://support.google.com/cloud/answer/9110914) ($15,000 to $75,000) for this. You can read more about this [here](https://www.theregister.com/2019/02/11/google_gmail_developer/).
 
-OAuth for Yandex is supported via the quick setup wizard.
+OAuth for Yandex and Yahoo is supported via the quick setup wizard.
 
 OAuth for Office 365 accounts is supported, but Microsoft does not offer OAuth for Outlook, Live and Hotmail accounts (yet?).
 
-OAuth access for Yahoo was requested, but Yahoo never responded to the request. OAuth for AOL [was deactivated](https://www.programmableweb.com/api/aol-open-auth) by AOL. Verizon owns both AOL and Yahoo, collectively named [Oath inc](https://en.wikipedia.org/wiki/Verizon_Media). So, it is reasonable to assume that OAuth is not supported by Yahoo anymore too.
-
 <br />
 
 <a name="faq112"></a>
@@ -2302,8 +2301,6 @@ FairEmail groups messages based on the standard *Message-ID*, *In-Reply-To* and
 
 When FairEmail cannot connect to an email server to receive messages, for example when the internet connection is bad or a firewall or a VPN is blocking the connection, FairEmail will wait 8, 16 and 32 seconds while keeping the device awake (=use battery power) and try again to connect. If this fails, FairEmail will schedule an alarm to retry after 15, 30 and 60 minutes and let the device sleep (=no battery usage).
 
-Between connectivity changes there is a wait of 90 seconds to give the email server the opportunity to discover the old connection is broken. This is necessary because the internet connection of a mobile device is often lost abruptly and to prevent the problem described in [this FAQ](#user-content-faq23).
-
 Note that [Android doze mode](https://developer.android.com/training/monitoring-device-state/doze-standby) does not allow to wake the device earlier than after 15 minutes.
 
 *Force sync* in the three-dots menu of the unified inbox can be used to let FairEmail attempt to reconnect without waiting.
@@ -2777,6 +2774,8 @@ Updating once a week will probably be sufficient, please see [here](https://gith
 
 Permanent deletion means that messages will *irreversibly* be lost, and to prevent this from happening accidentally, this always needs to be confirmed. Even with a confirmation, some very angry people who lost some of their messages through their own fault contacted me, which was a rather unpleasant experience :-(
 
+Advanced: the IMAP delete flag in combination with the EXPUNGE command is not supportable because both email servers and not all people can handle this, risking unexpected loss of messages. A complicating factor is that not all email servers support [UID EXPUNGE](https://tools.ietf.org/html/rfc4315).
+
 <br />
 
 <a name="faq161"></a>
diff --git a/docs/FAQ-de-rDE.md b/docs/FAQ-de-rDE.md
index a0bd0648f0..2b9603de63 100644
--- a/docs/FAQ-de-rDE.md
+++ b/docs/FAQ-de-rDE.md
@@ -78,6 +78,7 @@ Verwandte Fragen:
 * Eine Vorschau eines Nachrichtentextes wird auf Samsung-Uhren nicht (immer) angezeigt, weil [setLocalOnly](https://developer.android.com/reference/androidx/core/app/NotificationCompat.Builder.html#setLocalOnly(boolean)) wohl ignoriert wird. Bisher ist nur bekannt, dass Nachrichtenvorschautexte auf den Smart-Armbändern „Pebble 2”, „Fitbit Charge 3”, „Mi Band 3” und „Xiaomi Amazfit BIP” korrekt angezeigt werden. Siehe auch [diese FAQ](#user-content-faq126).
 * Ein [Fehler in Android 6.0](https://issuetracker.google.com/issues/37068143) verursacht einen Absturz mit * … Ungültiger Offset: ... Der gültige Bereich ist …* wenn Text ausgewählt ist und außerhalb des ausgewählten Textes angetippt wird. Dieser Fehler wurde in Android 6.0.1 behoben.
 * Interne (Anker-)Links funktionieren nicht, da die Originalnachrichten in einer eingebetteten Web-Ansicht in einer scrollenden Ansicht (der Konversationsliste) angezeigt werden. Dies ist eine Einschränkung von Android, die nicht behoben oder umgangen werden kann.
+* Language detection [is not working anymore](https://issuetracker.google.com/issues/173337263) on Pixel devices with (upgraded to?) Android 11
 
 ## Geplante Funktionen
 
@@ -861,7 +862,7 @@ The error *... Connection refused ...* means that the email server or something
 
 The error *... Network unreachable ...* means that the email server was not reachable via the current internet connection, for example because internet traffic is restricted to local traffic only.
 
-The error *... Host is unresolved ...* or "*... Unable to resolve host ...* means that the address of the email server could not be resolved. This might be caused by ad blocking or an unreachable or not properly working [DNS](https://en.wikipedia.org/wiki/Domain_Name_System) server.
+The error *... Host is unresolved ...*, *... Unable to resolve host ...* or *... No address associated with hostname ...* means that the address of the email server could not be resolved into an IP address. This might be caused by a VPN, ad blocking or an unreachable or not properly working (local) [DNS](https://en.wikipedia.org/wiki/Domain_Name_System) server.
 
 The error *... Software caused connection abort ...* means that the email server or something between FairEmail and the email server actively terminated an existing connection. This can for example happen when connectivity was abruptly lost. A typical example is turning on flight mode.
 
@@ -2162,14 +2163,12 @@ Disabling *Partial fetch* will result in more memory usage.
 <a name="faq111"></a>
 **(111) Is OAuth supported?**
 
-OAuth for Gmail is supported via the quick setup wizard. The Android account manager will be used to fetch and refresh OAuth tokens for selected on-device accounts. OAuth for non on-device accounts is not supported because Google requires a [yearly security audit](https://support.google.com/cloud/answer/9110914) ($15,000 to $75,000) for this.
+OAuth for Gmail is supported via the quick setup wizard. The Android account manager will be used to fetch and refresh OAuth tokens for selected on-device accounts. OAuth for non on-device accounts is not supported because Google requires a [yearly security audit](https://support.google.com/cloud/answer/9110914) ($15,000 to $75,000) for this. You can read more about this [here](https://www.theregister.com/2019/02/11/google_gmail_developer/).
 
-OAuth for Yandex is supported via the quick setup wizard.
+OAuth for Yandex and Yahoo is supported via the quick setup wizard.
 
 OAuth for Office 365 accounts is supported, but Microsoft does not offer OAuth for Outlook, Live and Hotmail accounts (yet?).
 
-OAuth access for Yahoo was requested, but Yahoo never responded to the request. OAuth for AOL [was deactivated](https://www.programmableweb.com/api/aol-open-auth) by AOL. Verizon owns both AOL and Yahoo, collectively named [Oath inc](https://en.wikipedia.org/wiki/Verizon_Media). So, it is reasonable to assume that OAuth is not supported by Yahoo anymore too.
-
 <br />
 
 <a name="faq112"></a>
@@ -2302,8 +2301,6 @@ FairEmail groups messages based on the standard *Message-ID*, *In-Reply-To* and
 
 When FairEmail cannot connect to an email server to receive messages, for example when the internet connection is bad or a firewall or a VPN is blocking the connection, FairEmail will wait 8, 16 and 32 seconds while keeping the device awake (=use battery power) and try again to connect. If this fails, FairEmail will schedule an alarm to retry after 15, 30 and 60 minutes and let the device sleep (=no battery usage).
 
-Between connectivity changes there is a wait of 90 seconds to give the email server the opportunity to discover the old connection is broken. This is necessary because the internet connection of a mobile device is often lost abruptly and to prevent the problem described in [this FAQ](#user-content-faq23).
-
 Note that [Android doze mode](https://developer.android.com/training/monitoring-device-state/doze-standby) does not allow to wake the device earlier than after 15 minutes.
 
 *Force sync* in the three-dots menu of the unified inbox can be used to let FairEmail attempt to reconnect without waiting.
@@ -2777,6 +2774,8 @@ Updating once a week will probably be sufficient, please see [here](https://gith
 
 Permanent deletion means that messages will *irreversibly* be lost, and to prevent this from happening accidentally, this always needs to be confirmed. Even with a confirmation, some very angry people who lost some of their messages through their own fault contacted me, which was a rather unpleasant experience :-(
 
+Advanced: the IMAP delete flag in combination with the EXPUNGE command is not supportable because both email servers and not all people can handle this, risking unexpected loss of messages. A complicating factor is that not all email servers support [UID EXPUNGE](https://tools.ietf.org/html/rfc4315).
+
 <br />
 
 <a name="faq161"></a>
diff --git a/docs/FAQ-de-rLI.md b/docs/FAQ-de-rLI.md
index a0bd0648f0..2b9603de63 100644
--- a/docs/FAQ-de-rLI.md
+++ b/docs/FAQ-de-rLI.md
@@ -78,6 +78,7 @@ Verwandte Fragen:
 * Eine Vorschau eines Nachrichtentextes wird auf Samsung-Uhren nicht (immer) angezeigt, weil [setLocalOnly](https://developer.android.com/reference/androidx/core/app/NotificationCompat.Builder.html#setLocalOnly(boolean)) wohl ignoriert wird. Bisher ist nur bekannt, dass Nachrichtenvorschautexte auf den Smart-Armbändern „Pebble 2”, „Fitbit Charge 3”, „Mi Band 3” und „Xiaomi Amazfit BIP” korrekt angezeigt werden. Siehe auch [diese FAQ](#user-content-faq126).
 * Ein [Fehler in Android 6.0](https://issuetracker.google.com/issues/37068143) verursacht einen Absturz mit * … Ungültiger Offset: ... Der gültige Bereich ist …* wenn Text ausgewählt ist und außerhalb des ausgewählten Textes angetippt wird. Dieser Fehler wurde in Android 6.0.1 behoben.
 * Interne (Anker-)Links funktionieren nicht, da die Originalnachrichten in einer eingebetteten Web-Ansicht in einer scrollenden Ansicht (der Konversationsliste) angezeigt werden. Dies ist eine Einschränkung von Android, die nicht behoben oder umgangen werden kann.
+* Language detection [is not working anymore](https://issuetracker.google.com/issues/173337263) on Pixel devices with (upgraded to?) Android 11
 
 ## Geplante Funktionen
 
@@ -861,7 +862,7 @@ The error *... Connection refused ...* means that the email server or something
 
 The error *... Network unreachable ...* means that the email server was not reachable via the current internet connection, for example because internet traffic is restricted to local traffic only.
 
-The error *... Host is unresolved ...* or "*... Unable to resolve host ...* means that the address of the email server could not be resolved. This might be caused by ad blocking or an unreachable or not properly working [DNS](https://en.wikipedia.org/wiki/Domain_Name_System) server.
+The error *... Host is unresolved ...*, *... Unable to resolve host ...* or *... No address associated with hostname ...* means that the address of the email server could not be resolved into an IP address. This might be caused by a VPN, ad blocking or an unreachable or not properly working (local) [DNS](https://en.wikipedia.org/wiki/Domain_Name_System) server.
 
 The error *... Software caused connection abort ...* means that the email server or something between FairEmail and the email server actively terminated an existing connection. This can for example happen when connectivity was abruptly lost. A typical example is turning on flight mode.
 
@@ -2162,14 +2163,12 @@ Disabling *Partial fetch* will result in more memory usage.
 <a name="faq111"></a>
 **(111) Is OAuth supported?**
 
-OAuth for Gmail is supported via the quick setup wizard. The Android account manager will be used to fetch and refresh OAuth tokens for selected on-device accounts. OAuth for non on-device accounts is not supported because Google requires a [yearly security audit](https://support.google.com/cloud/answer/9110914) ($15,000 to $75,000) for this.
+OAuth for Gmail is supported via the quick setup wizard. The Android account manager will be used to fetch and refresh OAuth tokens for selected on-device accounts. OAuth for non on-device accounts is not supported because Google requires a [yearly security audit](https://support.google.com/cloud/answer/9110914) ($15,000 to $75,000) for this. You can read more about this [here](https://www.theregister.com/2019/02/11/google_gmail_developer/).
 
-OAuth for Yandex is supported via the quick setup wizard.
+OAuth for Yandex and Yahoo is supported via the quick setup wizard.
 
 OAuth for Office 365 accounts is supported, but Microsoft does not offer OAuth for Outlook, Live and Hotmail accounts (yet?).
 
-OAuth access for Yahoo was requested, but Yahoo never responded to the request. OAuth for AOL [was deactivated](https://www.programmableweb.com/api/aol-open-auth) by AOL. Verizon owns both AOL and Yahoo, collectively named [Oath inc](https://en.wikipedia.org/wiki/Verizon_Media). So, it is reasonable to assume that OAuth is not supported by Yahoo anymore too.
-
 <br />
 
 <a name="faq112"></a>
@@ -2302,8 +2301,6 @@ FairEmail groups messages based on the standard *Message-ID*, *In-Reply-To* and
 
 When FairEmail cannot connect to an email server to receive messages, for example when the internet connection is bad or a firewall or a VPN is blocking the connection, FairEmail will wait 8, 16 and 32 seconds while keeping the device awake (=use battery power) and try again to connect. If this fails, FairEmail will schedule an alarm to retry after 15, 30 and 60 minutes and let the device sleep (=no battery usage).
 
-Between connectivity changes there is a wait of 90 seconds to give the email server the opportunity to discover the old connection is broken. This is necessary because the internet connection of a mobile device is often lost abruptly and to prevent the problem described in [this FAQ](#user-content-faq23).
-
 Note that [Android doze mode](https://developer.android.com/training/monitoring-device-state/doze-standby) does not allow to wake the device earlier than after 15 minutes.
 
 *Force sync* in the three-dots menu of the unified inbox can be used to let FairEmail attempt to reconnect without waiting.
@@ -2777,6 +2774,8 @@ Updating once a week will probably be sufficient, please see [here](https://gith
 
 Permanent deletion means that messages will *irreversibly* be lost, and to prevent this from happening accidentally, this always needs to be confirmed. Even with a confirmation, some very angry people who lost some of their messages through their own fault contacted me, which was a rather unpleasant experience :-(
 
+Advanced: the IMAP delete flag in combination with the EXPUNGE command is not supportable because both email servers and not all people can handle this, risking unexpected loss of messages. A complicating factor is that not all email servers support [UID EXPUNGE](https://tools.ietf.org/html/rfc4315).
+
 <br />
 
 <a name="faq161"></a>
diff --git a/docs/FAQ-el-rGR.md b/docs/FAQ-el-rGR.md
index ce71325db1..1cec151594 100644
--- a/docs/FAQ-el-rGR.md
+++ b/docs/FAQ-el-rGR.md
@@ -78,6 +78,7 @@ Related questions:
 * A preview of a message text doesn't (always) appear on Samsung watches because [setLocalOnly](https://developer.android.com/reference/androidx/core/app/NotificationCompat.Builder.html#setLocalOnly(boolean)) seem to be ignored. Message preview texts are known to be displayed correctly on Pebble 2, Fitbit Charge 3, Mi band 3, and Xiaomi Amazfit BIP wearables. See also [this FAQ](#user-content-faq126).
 * A [bug in Android 6.0](https://issuetracker.google.com/issues/37068143) causes a crash with *... Invalid offset: ... Valid range is ...* when text is selected and tapping outside of the selected text. This bug has been fixed in Android 6.0.1.
 * Internal (anchor) links will not work because original messages are shown in an embedded WebView in a scrolling view (the conversation list). This is an Android limitation which cannot be fixed or worked around.
+* Language detection [is not working anymore](https://issuetracker.google.com/issues/173337263) on Pixel devices with (upgraded to?) Android 11
 
 ## Planned features
 
@@ -861,7 +862,7 @@ The error *... Connection refused ...* means that the email server or something
 
 The error *... Network unreachable ...* means that the email server was not reachable via the current internet connection, for example because internet traffic is restricted to local traffic only.
 
-The error *... Host is unresolved ...* or "*... Unable to resolve host ...* means that the address of the email server could not be resolved. This might be caused by ad blocking or an unreachable or not properly working [DNS](https://en.wikipedia.org/wiki/Domain_Name_System) server.
+The error *... Host is unresolved ...*, *... Unable to resolve host ...* or *... No address associated with hostname ...* means that the address of the email server could not be resolved into an IP address. This might be caused by a VPN, ad blocking or an unreachable or not properly working (local) [DNS](https://en.wikipedia.org/wiki/Domain_Name_System) server.
 
 The error *... Software caused connection abort ...* means that the email server or something between FairEmail and the email server actively terminated an existing connection. This can for example happen when connectivity was abruptly lost. A typical example is turning on flight mode.
 
@@ -2162,14 +2163,12 @@ Disabling *Partial fetch* will result in more memory usage.
 <a name="faq111"></a>
 **(111) Is OAuth supported?**
 
-OAuth for Gmail is supported via the quick setup wizard. The Android account manager will be used to fetch and refresh OAuth tokens for selected on-device accounts. OAuth for non on-device accounts is not supported because Google requires a [yearly security audit](https://support.google.com/cloud/answer/9110914) ($15,000 to $75,000) for this.
+OAuth for Gmail is supported via the quick setup wizard. The Android account manager will be used to fetch and refresh OAuth tokens for selected on-device accounts. OAuth for non on-device accounts is not supported because Google requires a [yearly security audit](https://support.google.com/cloud/answer/9110914) ($15,000 to $75,000) for this. You can read more about this [here](https://www.theregister.com/2019/02/11/google_gmail_developer/).
 
-OAuth for Yandex is supported via the quick setup wizard.
+OAuth for Yandex and Yahoo is supported via the quick setup wizard.
 
 OAuth for Office 365 accounts is supported, but Microsoft does not offer OAuth for Outlook, Live and Hotmail accounts (yet?).
 
-OAuth access for Yahoo was requested, but Yahoo never responded to the request. OAuth for AOL [was deactivated](https://www.programmableweb.com/api/aol-open-auth) by AOL. Verizon owns both AOL and Yahoo, collectively named [Oath inc](https://en.wikipedia.org/wiki/Verizon_Media). So, it is reasonable to assume that OAuth is not supported by Yahoo anymore too.
-
 <br />
 
 <a name="faq112"></a>
@@ -2302,8 +2301,6 @@ FairEmail groups messages based on the standard *Message-ID*, *In-Reply-To* and
 
 When FairEmail cannot connect to an email server to receive messages, for example when the internet connection is bad or a firewall or a VPN is blocking the connection, FairEmail will wait 8, 16 and 32 seconds while keeping the device awake (=use battery power) and try again to connect. If this fails, FairEmail will schedule an alarm to retry after 15, 30 and 60 minutes and let the device sleep (=no battery usage).
 
-Between connectivity changes there is a wait of 90 seconds to give the email server the opportunity to discover the old connection is broken. This is necessary because the internet connection of a mobile device is often lost abruptly and to prevent the problem described in [this FAQ](#user-content-faq23).
-
 Note that [Android doze mode](https://developer.android.com/training/monitoring-device-state/doze-standby) does not allow to wake the device earlier than after 15 minutes.
 
 *Force sync* in the three-dots menu of the unified inbox can be used to let FairEmail attempt to reconnect without waiting.
@@ -2777,6 +2774,8 @@ Updating once a week will probably be sufficient, please see [here](https://gith
 
 Permanent deletion means that messages will *irreversibly* be lost, and to prevent this from happening accidentally, this always needs to be confirmed. Even with a confirmation, some very angry people who lost some of their messages through their own fault contacted me, which was a rather unpleasant experience :-(
 
+Advanced: the IMAP delete flag in combination with the EXPUNGE command is not supportable because both email servers and not all people can handle this, risking unexpected loss of messages. A complicating factor is that not all email servers support [UID EXPUNGE](https://tools.ietf.org/html/rfc4315).
+
 <br />
 
 <a name="faq161"></a>
diff --git a/docs/FAQ-en-rGB.md b/docs/FAQ-en-rGB.md
index 340ced3c42..fa50e84820 100644
--- a/docs/FAQ-en-rGB.md
+++ b/docs/FAQ-en-rGB.md
@@ -78,6 +78,7 @@ Related questions:
 * A preview of a message text doesn't (always) appear on Samsung watches because [setLocalOnly](https://developer.android.com/reference/androidx/core/app/NotificationCompat.Builder.html#setLocalOnly(boolean)) seem to be ignored. Message preview texts are known to be displayed correctly on Pebble 2, Fitbit Charge 3, Mi band 3, and Xiaomi Amazfit BIP wearables. See also [this FAQ](#user-content-faq126).
 * A [bug in Android 6.0](https://issuetracker.google.com/issues/37068143) causes a crash with *... Invalid offset: ... Valid range is ...* when text is selected and tapping outside of the selected text. This bug has been fixed in Android 6.0.1.
 * Internal (anchor) links will not work because original messages are shown in an embedded WebView in a scrolling view (the conversation list). This is an Android limitation which cannot be fixed or worked around.
+* Language detection [is not working anymore](https://issuetracker.google.com/issues/173337263) on Pixel devices with (upgraded to?) Android 11
 
 ## Planned features
 
@@ -861,7 +862,7 @@ The error *... Connection refused ...* means that the email server or something
 
 The error *... Network unreachable ...* means that the email server was not reachable via the current internet connection, for example because internet traffic is restricted to local traffic only.
 
-The error *... Host is unresolved ...* or "*... Unable to resolve host ...* means that the address of the email server could not be resolved. This might be caused by ad blocking or an unreachable or not properly working [DNS](https://en.wikipedia.org/wiki/Domain_Name_System) server.
+The error *... Host is unresolved ...*, *... Unable to resolve host ...* or *... No address associated with hostname ...* means that the address of the email server could not be resolved into an IP address. This might be caused by a VPN, ad blocking or an unreachable or not properly working (local) [DNS](https://en.wikipedia.org/wiki/Domain_Name_System) server.
 
 The error *... Software caused connection abort ...* means that the email server or something between FairEmail and the email server actively terminated an existing connection. This can for example happen when connectivity was abruptly lost. A typical example is turning on flight mode.
 
@@ -2162,14 +2163,12 @@ Disabling *Partial fetch* will result in more memory usage.
 <a name="faq111"></a>
 **(111) Is OAuth supported?**
 
-OAuth for Gmail is supported via the quick setup wizard. The Android account manager will be used to fetch and refresh OAuth tokens for selected on-device accounts. OAuth for non on-device accounts is not supported because Google requires a [yearly security audit](https://support.google.com/cloud/answer/9110914) ($15,000 to $75,000) for this.
+OAuth for Gmail is supported via the quick setup wizard. The Android account manager will be used to fetch and refresh OAuth tokens for selected on-device accounts. OAuth for non on-device accounts is not supported because Google requires a [yearly security audit](https://support.google.com/cloud/answer/9110914) ($15,000 to $75,000) for this. You can read more about this [here](https://www.theregister.com/2019/02/11/google_gmail_developer/).
 
-OAuth for Yandex is supported via the quick setup wizard.
+OAuth for Yandex and Yahoo is supported via the quick setup wizard.
 
 OAuth for Office 365 accounts is supported, but Microsoft does not offer OAuth for Outlook, Live and Hotmail accounts (yet?).
 
-OAuth access for Yahoo was requested, but Yahoo never responded to the request. OAuth for AOL [was deactivated](https://www.programmableweb.com/api/aol-open-auth) by AOL. Verizon owns both AOL and Yahoo, collectively named [Oath inc](https://en.wikipedia.org/wiki/Verizon_Media). So, it is reasonable to assume that OAuth is not supported by Yahoo anymore too.
-
 <br />
 
 <a name="faq112"></a>
@@ -2302,8 +2301,6 @@ FairEmail groups messages based on the standard *Message-ID*, *In-Reply-To* and
 
 When FairEmail cannot connect to an email server to receive messages, for example when the internet connection is bad or a firewall or a VPN is blocking the connection, FairEmail will wait 8, 16 and 32 seconds while keeping the device awake (=use battery power) and try again to connect. If this fails, FairEmail will schedule an alarm to retry after 15, 30 and 60 minutes and let the device sleep (=no battery usage).
 
-Between connectivity changes there is a wait of 90 seconds to give the email server the opportunity to discover the old connection is broken. This is necessary because the internet connection of a mobile device is often lost abruptly and to prevent the problem described in [this FAQ](#user-content-faq23).
-
 Note that [Android doze mode](https://developer.android.com/training/monitoring-device-state/doze-standby) does not allow to wake the device earlier than after 15 minutes.
 
 *Force sync* in the three-dots menu of the unified inbox can be used to let FairEmail attempt to reconnect without waiting.
@@ -2777,6 +2774,8 @@ Updating once a week will probably be sufficient, please see [here](https://gith
 
 Permanent deletion means that messages will *irreversibly* be lost, and to prevent this from happening accidentally, this always needs to be confirmed. Even with a confirmation, some very angry people who lost some of their messages through their own fault contacted me, which was a rather unpleasant experience :-(
 
+Advanced: the IMAP delete flag in combination with the EXPUNGE command is not supportable because both email servers and not all people can handle this, risking unexpected loss of messages. A complicating factor is that not all email servers support [UID EXPUNGE](https://tools.ietf.org/html/rfc4315).
+
 <br />
 
 <a name="faq161"></a>
diff --git a/docs/FAQ-es-rES.md b/docs/FAQ-es-rES.md
index d98459bb75..4e9395a976 100644
--- a/docs/FAQ-es-rES.md
+++ b/docs/FAQ-es-rES.md
@@ -78,6 +78,7 @@ Preguntas relacionadas:
 * La vista previa del texto de los mensajes no aparece (siempre) en los relojes de Samsung porque [setLocalOnly](https://developer.android.com/reference/androidx/core/app/NotificationCompat.Builder.html#setLocalOnly(boolean)) parece ser ignorado. Se sabe que los textos de vista previa de los mensajes se muestran correctamente en los wearables Pebble 2, Fitbit Charge 3, Mi band 3 y Xiaomi Amazfit BIP. Ver también [estas Preguntas Frecuentes](#user-content-faq126).
 * Un [error en Android 6.0](https://issuetracker.google.com/issues/37068143) causa un error con *... Offset inválido: ... El rango válido es ...* cuando el texto está seleccionado y se toca fuera del texto seleccionado. Este error ha sido corregido en Android 6.0.1.
 * Los enlaces internos (anchor) no funcionarán porque los mensajes originales se muestran en una WebView embebida en una vista de desplazamiento (la lista de conversaciones). Esta es una limitación de Android que no se puede arreglar o eludir.
+* La detección de idioma [ya no funciona](https://issuetracker.google.com/issues/173337263) en dispositivos Pixel con (¿actualizado a?) Android 11
 
 ## Características planificadas
 
@@ -861,7 +862,7 @@ El error *... Connection refused ...* means that the email server or something b
 
 El error *... Network unreachable ...* means that the email server was not reachable via the current internet connection, for example because internet traffic is restricted to local traffic only.
 
-El error *... Host is unresolved ...* or "*... Unable to resolve host ...* means that the address of the email server could not be resolved. This might be caused by ad blocking or an unreachable or not properly working [DNS](https://en.wikipedia.org/wiki/Domain_Name_System) server.
+El error *... Host is unresolved ...*, *... Unable to resolve host ...* or *... No address associated with hostname ...* means that the address of the email server could not be resolved into an IP address. This might be caused by a VPN, ad blocking or an unreachable or not properly working (local) [DNS](https://en.wikipedia.org/wiki/Domain_Name_System) server.
 
 The error *... Software caused connection abort ...* means that the email server or something between FairEmail and the email server actively terminated an existing connection. This can for example happen when connectivity was abruptly lost. A typical example is turning on flight mode.
 
@@ -2162,14 +2163,12 @@ Disabling *Partial fetch* will result in more memory usage.
 <a name="faq111"></a>
 **(111) Is OAuth supported?**
 
-OAuth for Gmail is supported via the quick setup wizard. The Android account manager will be used to fetch and refresh OAuth tokens for selected on-device accounts. OAuth for non on-device accounts is not supported because Google requires a [yearly security audit](https://support.google.com/cloud/answer/9110914) ($15,000 to $75,000) for this.
+OAuth for Gmail is supported via the quick setup wizard. The Android account manager will be used to fetch and refresh OAuth tokens for selected on-device accounts. OAuth for non on-device accounts is not supported because Google requires a [yearly security audit](https://support.google.com/cloud/answer/9110914) ($15,000 to $75,000) for this. You can read more about this [here](https://www.theregister.com/2019/02/11/google_gmail_developer/).
 
-OAuth for Yandex is supported via the quick setup wizard.
+OAuth for Yandex and Yahoo is supported via the quick setup wizard.
 
 OAuth for Office 365 accounts is supported, but Microsoft does not offer OAuth for Outlook, Live and Hotmail accounts (yet?).
 
-OAuth access for Yahoo was requested, but Yahoo never responded to the request. OAuth for AOL [was deactivated](https://www.programmableweb.com/api/aol-open-auth) by AOL. Verizon owns both AOL and Yahoo, collectively named [Oath inc](https://en.wikipedia.org/wiki/Verizon_Media). So, it is reasonable to assume that OAuth is not supported by Yahoo anymore too.
-
 <br />
 
 <a name="faq112"></a>
@@ -2302,8 +2301,6 @@ FairEmail groups messages based on the standard *Message-ID*, *In-Reply-To* and
 
 When FairEmail cannot connect to an email server to receive messages, for example when the internet connection is bad or a firewall or a VPN is blocking the connection, FairEmail will wait 8, 16 and 32 seconds while keeping the device awake (=use battery power) and try again to connect. If this fails, FairEmail will schedule an alarm to retry after 15, 30 and 60 minutes and let the device sleep (=no battery usage).
 
-Between connectivity changes there is a wait of 90 seconds to give the email server the opportunity to discover the old connection is broken. This is necessary because the internet connection of a mobile device is often lost abruptly and to prevent the problem described in [this FAQ](#user-content-faq23).
-
 Note that [Android doze mode](https://developer.android.com/training/monitoring-device-state/doze-standby) does not allow to wake the device earlier than after 15 minutes.
 
 *Force sync* in the three-dots menu of the unified inbox can be used to let FairEmail attempt to reconnect without waiting.
@@ -2777,6 +2774,8 @@ Updating once a week will probably be sufficient, please see [here](https://gith
 
 Permanent deletion means that messages will *irreversibly* be lost, and to prevent this from happening accidentally, this always needs to be confirmed. Even with a confirmation, some very angry people who lost some of their messages through their own fault contacted me, which was a rather unpleasant experience :-(
 
+Advanced: the IMAP delete flag in combination with the EXPUNGE command is not supportable because both email servers and not all people can handle this, risking unexpected loss of messages. A complicating factor is that not all email servers support [UID EXPUNGE](https://tools.ietf.org/html/rfc4315).
+
 <br />
 
 <a name="faq161"></a>
diff --git a/docs/FAQ-eu-rES.md b/docs/FAQ-eu-rES.md
index 7b7b451250..a593607a58 100644
--- a/docs/FAQ-eu-rES.md
+++ b/docs/FAQ-eu-rES.md
@@ -78,6 +78,7 @@ Related questions:
 * A preview of a message text doesn't (always) appear on Samsung watches because [setLocalOnly](https://developer.android.com/reference/androidx/core/app/NotificationCompat.Builder.html#setLocalOnly(boolean)) seem to be ignored. Message preview texts are known to be displayed correctly on Pebble 2, Fitbit Charge 3, Mi band 3, and Xiaomi Amazfit BIP wearables. See also [this FAQ](#user-content-faq126).
 * A [bug in Android 6.0](https://issuetracker.google.com/issues/37068143) causes a crash with *... Invalid offset: ... Valid range is ...* when text is selected and tapping outside of the selected text. This bug has been fixed in Android 6.0.1.
 * Internal (anchor) links will not work because original messages are shown in an embedded WebView in a scrolling view (the conversation list). This is an Android limitation which cannot be fixed or worked around.
+* Language detection [is not working anymore](https://issuetracker.google.com/issues/173337263) on Pixel devices with (upgraded to?) Android 11
 
 ## Planned features
 
@@ -861,7 +862,7 @@ The error *... Connection refused ...* means that the email server or something
 
 The error *... Network unreachable ...* means that the email server was not reachable via the current internet connection, for example because internet traffic is restricted to local traffic only.
 
-The error *... Host is unresolved ...* or "*... Unable to resolve host ...* means that the address of the email server could not be resolved. This might be caused by ad blocking or an unreachable or not properly working [DNS](https://en.wikipedia.org/wiki/Domain_Name_System) server.
+The error *... Host is unresolved ...*, *... Unable to resolve host ...* or *... No address associated with hostname ...* means that the address of the email server could not be resolved into an IP address. This might be caused by a VPN, ad blocking or an unreachable or not properly working (local) [DNS](https://en.wikipedia.org/wiki/Domain_Name_System) server.
 
 The error *... Software caused connection abort ...* means that the email server or something between FairEmail and the email server actively terminated an existing connection. This can for example happen when connectivity was abruptly lost. A typical example is turning on flight mode.
 
@@ -2162,14 +2163,12 @@ Disabling *Partial fetch* will result in more memory usage.
 <a name="faq111"></a>
 **(111) Is OAuth supported?**
 
-OAuth for Gmail is supported via the quick setup wizard. The Android account manager will be used to fetch and refresh OAuth tokens for selected on-device accounts. OAuth for non on-device accounts is not supported because Google requires a [yearly security audit](https://support.google.com/cloud/answer/9110914) ($15,000 to $75,000) for this.
+OAuth for Gmail is supported via the quick setup wizard. The Android account manager will be used to fetch and refresh OAuth tokens for selected on-device accounts. OAuth for non on-device accounts is not supported because Google requires a [yearly security audit](https://support.google.com/cloud/answer/9110914) ($15,000 to $75,000) for this. You can read more about this [here](https://www.theregister.com/2019/02/11/google_gmail_developer/).
 
-OAuth for Yandex is supported via the quick setup wizard.
+OAuth for Yandex and Yahoo is supported via the quick setup wizard.
 
 OAuth for Office 365 accounts is supported, but Microsoft does not offer OAuth for Outlook, Live and Hotmail accounts (yet?).
 
-OAuth access for Yahoo was requested, but Yahoo never responded to the request. OAuth for AOL [was deactivated](https://www.programmableweb.com/api/aol-open-auth) by AOL. Verizon owns both AOL and Yahoo, collectively named [Oath inc](https://en.wikipedia.org/wiki/Verizon_Media). So, it is reasonable to assume that OAuth is not supported by Yahoo anymore too.
-
 <br />
 
 <a name="faq112"></a>
@@ -2302,8 +2301,6 @@ FairEmail groups messages based on the standard *Message-ID*, *In-Reply-To* and
 
 When FairEmail cannot connect to an email server to receive messages, for example when the internet connection is bad or a firewall or a VPN is blocking the connection, FairEmail will wait 8, 16 and 32 seconds while keeping the device awake (=use battery power) and try again to connect. If this fails, FairEmail will schedule an alarm to retry after 15, 30 and 60 minutes and let the device sleep (=no battery usage).
 
-Between connectivity changes there is a wait of 90 seconds to give the email server the opportunity to discover the old connection is broken. This is necessary because the internet connection of a mobile device is often lost abruptly and to prevent the problem described in [this FAQ](#user-content-faq23).
-
 Note that [Android doze mode](https://developer.android.com/training/monitoring-device-state/doze-standby) does not allow to wake the device earlier than after 15 minutes.
 
 *Force sync* in the three-dots menu of the unified inbox can be used to let FairEmail attempt to reconnect without waiting.
@@ -2777,6 +2774,8 @@ Updating once a week will probably be sufficient, please see [here](https://gith
 
 Permanent deletion means that messages will *irreversibly* be lost, and to prevent this from happening accidentally, this always needs to be confirmed. Even with a confirmation, some very angry people who lost some of their messages through their own fault contacted me, which was a rather unpleasant experience :-(
 
+Advanced: the IMAP delete flag in combination with the EXPUNGE command is not supportable because both email servers and not all people can handle this, risking unexpected loss of messages. A complicating factor is that not all email servers support [UID EXPUNGE](https://tools.ietf.org/html/rfc4315).
+
 <br />
 
 <a name="faq161"></a>
diff --git a/docs/FAQ-fa-rIR.md b/docs/FAQ-fa-rIR.md
index 3455feb844..934a0b4a94 100644
--- a/docs/FAQ-fa-rIR.md
+++ b/docs/FAQ-fa-rIR.md
@@ -78,6 +78,7 @@ Please see [here](#user-content-faq22) for common error messages and solutions.
 * A preview of a message text doesn't (always) appear on Samsung watches because [setLocalOnly](https://developer.android.com/reference/androidx/core/app/NotificationCompat.Builder.html#setLocalOnly(boolean)) seem to be ignored. Message preview texts are known to be displayed correctly on Pebble 2, Fitbit Charge 3, Mi band 3, and Xiaomi Amazfit BIP wearables. See also [this FAQ](#user-content-faq126).
 * A [bug in Android 6.0](https://issuetracker.google.com/issues/37068143) causes a crash with *... Invalid offset: ... Valid range is ...* when text is selected and tapping outside of the selected text. This bug has been fixed in Android 6.0.1.
 * Internal (anchor) links will not work because original messages are shown in an embedded WebView in a scrolling view (the conversation list). This is an Android limitation which cannot be fixed or worked around.
+* Language detection [is not working anymore](https://issuetracker.google.com/issues/173337263) on Pixel devices with (upgraded to?) Android 11
 
 ## ویژگی‌های برنامه‌ریزی شده
 
@@ -861,7 +862,7 @@ The error *... Connection refused ...* means that the email server or something
 
 The error *... Network unreachable ...* means that the email server was not reachable via the current internet connection, for example because internet traffic is restricted to local traffic only.
 
-The error *... Host is unresolved ...* or "*... Unable to resolve host ...* means that the address of the email server could not be resolved. This might be caused by ad blocking or an unreachable or not properly working [DNS](https://en.wikipedia.org/wiki/Domain_Name_System) server.
+The error *... Host is unresolved ...*, *... Unable to resolve host ...* or *... No address associated with hostname ...* means that the address of the email server could not be resolved into an IP address. This might be caused by a VPN, ad blocking or an unreachable or not properly working (local) [DNS](https://en.wikipedia.org/wiki/Domain_Name_System) server.
 
 The error *... Software caused connection abort ...* means that the email server or something between FairEmail and the email server actively terminated an existing connection. This can for example happen when connectivity was abruptly lost. A typical example is turning on flight mode.
 
@@ -2162,14 +2163,12 @@ Disabling *Partial fetch* will result in more memory usage.
 <a name="faq111"></a>
 **(111) Is OAuth supported?**
 
-OAuth for Gmail is supported via the quick setup wizard. The Android account manager will be used to fetch and refresh OAuth tokens for selected on-device accounts. OAuth for non on-device accounts is not supported because Google requires a [yearly security audit](https://support.google.com/cloud/answer/9110914) ($15,000 to $75,000) for this.
+OAuth for Gmail is supported via the quick setup wizard. The Android account manager will be used to fetch and refresh OAuth tokens for selected on-device accounts. OAuth for non on-device accounts is not supported because Google requires a [yearly security audit](https://support.google.com/cloud/answer/9110914) ($15,000 to $75,000) for this. You can read more about this [here](https://www.theregister.com/2019/02/11/google_gmail_developer/).
 
-OAuth for Yandex is supported via the quick setup wizard.
+OAuth for Yandex and Yahoo is supported via the quick setup wizard.
 
 OAuth for Office 365 accounts is supported, but Microsoft does not offer OAuth for Outlook, Live and Hotmail accounts (yet?).
 
-OAuth access for Yahoo was requested, but Yahoo never responded to the request. OAuth for AOL [was deactivated](https://www.programmableweb.com/api/aol-open-auth) by AOL. Verizon owns both AOL and Yahoo, collectively named [Oath inc](https://en.wikipedia.org/wiki/Verizon_Media). So, it is reasonable to assume that OAuth is not supported by Yahoo anymore too.
-
 <br />
 
 <a name="faq112"></a>
@@ -2302,8 +2301,6 @@ FairEmail groups messages based on the standard *Message-ID*, *In-Reply-To* and
 
 When FairEmail cannot connect to an email server to receive messages, for example when the internet connection is bad or a firewall or a VPN is blocking the connection, FairEmail will wait 8, 16 and 32 seconds while keeping the device awake (=use battery power) and try again to connect. If this fails, FairEmail will schedule an alarm to retry after 15, 30 and 60 minutes and let the device sleep (=no battery usage).
 
-Between connectivity changes there is a wait of 90 seconds to give the email server the opportunity to discover the old connection is broken. This is necessary because the internet connection of a mobile device is often lost abruptly and to prevent the problem described in [this FAQ](#user-content-faq23).
-
 Note that [Android doze mode](https://developer.android.com/training/monitoring-device-state/doze-standby) does not allow to wake the device earlier than after 15 minutes.
 
 *Force sync* in the three-dots menu of the unified inbox can be used to let FairEmail attempt to reconnect without waiting.
@@ -2777,6 +2774,8 @@ Updating once a week will probably be sufficient, please see [here](https://gith
 
 Permanent deletion means that messages will *irreversibly* be lost, and to prevent this from happening accidentally, this always needs to be confirmed. Even with a confirmation, some very angry people who lost some of their messages through their own fault contacted me, which was a rather unpleasant experience :-(
 
+Advanced: the IMAP delete flag in combination with the EXPUNGE command is not supportable because both email servers and not all people can handle this, risking unexpected loss of messages. A complicating factor is that not all email servers support [UID EXPUNGE](https://tools.ietf.org/html/rfc4315).
+
 <br />
 
 <a name="faq161"></a>
diff --git a/docs/FAQ-fi-rFI.md b/docs/FAQ-fi-rFI.md
index 4d0cbe5052..41d8eec36f 100644
--- a/docs/FAQ-fi-rFI.md
+++ b/docs/FAQ-fi-rFI.md
@@ -78,6 +78,7 @@ Aiheeseen liittyvät kysymykset:
 * A preview of a message text doesn't (always) appear on Samsung watches because [setLocalOnly](https://developer.android.com/reference/androidx/core/app/NotificationCompat.Builder.html#setLocalOnly(boolean)) seem to be ignored. Message preview texts are known to be displayed correctly on Pebble 2, Fitbit Charge 3, Mi band 3, and Xiaomi Amazfit BIP wearables. See also [this FAQ](#user-content-faq126).
 * A [bug in Android 6.0](https://issuetracker.google.com/issues/37068143) causes a crash with *... Invalid offset: ... Valid range is ...* when text is selected and tapping outside of the selected text. This bug has been fixed in Android 6.0.1.
 * Internal (anchor) links will not work because original messages are shown in an embedded WebView in a scrolling view (the conversation list). This is an Android limitation which cannot be fixed or worked around.
+* Language detection [is not working anymore](https://issuetracker.google.com/issues/173337263) on Pixel devices with (upgraded to?) Android 11
 
 ## Suunnitellut ominaisuudet
 
@@ -861,7 +862,7 @@ The error *... Connection refused ...* means that the email server or something
 
 The error *... Network unreachable ...* means that the email server was not reachable via the current internet connection, for example because internet traffic is restricted to local traffic only.
 
-The error *... Host is unresolved ...* or "*... Unable to resolve host ...* means that the address of the email server could not be resolved. This might be caused by ad blocking or an unreachable or not properly working [DNS](https://en.wikipedia.org/wiki/Domain_Name_System) server.
+The error *... Host is unresolved ...*, *... Unable to resolve host ...* or *... No address associated with hostname ...* means that the address of the email server could not be resolved into an IP address. This might be caused by a VPN, ad blocking or an unreachable or not properly working (local) [DNS](https://en.wikipedia.org/wiki/Domain_Name_System) server.
 
 The error *... Software caused connection abort ...* means that the email server or something between FairEmail and the email server actively terminated an existing connection. This can for example happen when connectivity was abruptly lost. A typical example is turning on flight mode.
 
@@ -2162,14 +2163,12 @@ Disabling *Partial fetch* will result in more memory usage.
 <a name="faq111"></a>
 **(111) Is OAuth supported?**
 
-OAuth for Gmail is supported via the quick setup wizard. The Android account manager will be used to fetch and refresh OAuth tokens for selected on-device accounts. OAuth for non on-device accounts is not supported because Google requires a [yearly security audit](https://support.google.com/cloud/answer/9110914) ($15,000 to $75,000) for this.
+OAuth for Gmail is supported via the quick setup wizard. The Android account manager will be used to fetch and refresh OAuth tokens for selected on-device accounts. OAuth for non on-device accounts is not supported because Google requires a [yearly security audit](https://support.google.com/cloud/answer/9110914) ($15,000 to $75,000) for this. You can read more about this [here](https://www.theregister.com/2019/02/11/google_gmail_developer/).
 
-OAuth for Yandex is supported via the quick setup wizard.
+OAuth for Yandex and Yahoo is supported via the quick setup wizard.
 
 OAuth for Office 365 accounts is supported, but Microsoft does not offer OAuth for Outlook, Live and Hotmail accounts (yet?).
 
-OAuth access for Yahoo was requested, but Yahoo never responded to the request. OAuth for AOL [was deactivated](https://www.programmableweb.com/api/aol-open-auth) by AOL. Verizon owns both AOL and Yahoo, collectively named [Oath inc](https://en.wikipedia.org/wiki/Verizon_Media). So, it is reasonable to assume that OAuth is not supported by Yahoo anymore too.
-
 <br />
 
 <a name="faq112"></a>
@@ -2302,8 +2301,6 @@ FairEmail groups messages based on the standard *Message-ID*, *In-Reply-To* and
 
 When FairEmail cannot connect to an email server to receive messages, for example when the internet connection is bad or a firewall or a VPN is blocking the connection, FairEmail will wait 8, 16 and 32 seconds while keeping the device awake (=use battery power) and try again to connect. If this fails, FairEmail will schedule an alarm to retry after 15, 30 and 60 minutes and let the device sleep (=no battery usage).
 
-Between connectivity changes there is a wait of 90 seconds to give the email server the opportunity to discover the old connection is broken. This is necessary because the internet connection of a mobile device is often lost abruptly and to prevent the problem described in [this FAQ](#user-content-faq23).
-
 Note that [Android doze mode](https://developer.android.com/training/monitoring-device-state/doze-standby) does not allow to wake the device earlier than after 15 minutes.
 
 *Force sync* in the three-dots menu of the unified inbox can be used to let FairEmail attempt to reconnect without waiting.
@@ -2777,6 +2774,8 @@ Updating once a week will probably be sufficient, please see [here](https://gith
 
 Permanent deletion means that messages will *irreversibly* be lost, and to prevent this from happening accidentally, this always needs to be confirmed. Even with a confirmation, some very angry people who lost some of their messages through their own fault contacted me, which was a rather unpleasant experience :-(
 
+Advanced: the IMAP delete flag in combination with the EXPUNGE command is not supportable because both email servers and not all people can handle this, risking unexpected loss of messages. A complicating factor is that not all email servers support [UID EXPUNGE](https://tools.ietf.org/html/rfc4315).
+
 <br />
 
 <a name="faq161"></a>
diff --git a/docs/FAQ-fr-rCA.md b/docs/FAQ-fr-rCA.md
index 62fc35cb1c..3a584783ea 100644
--- a/docs/FAQ-fr-rCA.md
+++ b/docs/FAQ-fr-rCA.md
@@ -78,6 +78,7 @@ Questions liées:
 * Un aperçu d'un message texte n'apparaît pas (toujours) sur les montres Samsung car [setLocalOnly](https://developer.android.com/reference/androidx/core/app/NotificationCompat.Builder.html#setLocalOnly(boolean)) semble être ignoré. Les textes de prévisualisation des messages sont censés être affichés correctement sur les objets connectés Pebble 2, Fitbit Charge 3, Mi band 3 et Xiaomi Amazfit BIP. Voir aussi [cette FAQ](#user-content-faq126).
 * Un [bug sur Android 6.0](https://issuetracker.google.com/issues/37068143) provoque un plantage *... Invalid offset: ... Valid range is ...* lorsque du texte est sélectionné et en tapotant à côté de ce dernier. Ce bogue a été corrigé dans Android 6.0.1.
 * Les liens internes (ancrés) ne fonctionneront pas parce que les messages originaux sont affichés dans une WebView intégrée dans une vue défilante (la liste des conversations). Il s'agit d'une limitation Android qui ne peut être ni corrigée ni contournée.
+* Language detection [is not working anymore](https://issuetracker.google.com/issues/173337263) on Pixel devices with (upgraded to?) Android 11
 
 ## Fonctionnalités prévues
 
@@ -861,7 +862,7 @@ The error *... Connection refused ...* means that the email server or something
 
 The error *... Network unreachable ...* means that the email server was not reachable via the current internet connection, for example because internet traffic is restricted to local traffic only.
 
-The error *... Host is unresolved ...* or "*... Unable to resolve host ...* means that the address of the email server could not be resolved. This might be caused by ad blocking or an unreachable or not properly working [DNS](https://en.wikipedia.org/wiki/Domain_Name_System) server.
+The error *... Host is unresolved ...*, *... Unable to resolve host ...* or *... No address associated with hostname ...* means that the address of the email server could not be resolved into an IP address. This might be caused by a VPN, ad blocking or an unreachable or not properly working (local) [DNS](https://en.wikipedia.org/wiki/Domain_Name_System) server.
 
 The error *... Software caused connection abort ...* means that the email server or something between FairEmail and the email server actively terminated an existing connection. This can for example happen when connectivity was abruptly lost. A typical example is turning on flight mode.
 
@@ -2162,14 +2163,12 @@ Disabling *Partial fetch* will result in more memory usage.
 <a name="faq111"></a>
 **(111) Is OAuth supported?**
 
-OAuth for Gmail is supported via the quick setup wizard. The Android account manager will be used to fetch and refresh OAuth tokens for selected on-device accounts. OAuth for non on-device accounts is not supported because Google requires a [yearly security audit](https://support.google.com/cloud/answer/9110914) ($15,000 to $75,000) for this.
+OAuth for Gmail is supported via the quick setup wizard. The Android account manager will be used to fetch and refresh OAuth tokens for selected on-device accounts. OAuth for non on-device accounts is not supported because Google requires a [yearly security audit](https://support.google.com/cloud/answer/9110914) ($15,000 to $75,000) for this. You can read more about this [here](https://www.theregister.com/2019/02/11/google_gmail_developer/).
 
-OAuth for Yandex is supported via the quick setup wizard.
+OAuth for Yandex and Yahoo is supported via the quick setup wizard.
 
 OAuth for Office 365 accounts is supported, but Microsoft does not offer OAuth for Outlook, Live and Hotmail accounts (yet?).
 
-OAuth access for Yahoo was requested, but Yahoo never responded to the request. OAuth for AOL [was deactivated](https://www.programmableweb.com/api/aol-open-auth) by AOL. Verizon owns both AOL and Yahoo, collectively named [Oath inc](https://en.wikipedia.org/wiki/Verizon_Media). So, it is reasonable to assume that OAuth is not supported by Yahoo anymore too.
-
 <br />
 
 <a name="faq112"></a>
@@ -2302,8 +2301,6 @@ FairEmail groups messages based on the standard *Message-ID*, *In-Reply-To* and
 
 When FairEmail cannot connect to an email server to receive messages, for example when the internet connection is bad or a firewall or a VPN is blocking the connection, FairEmail will wait 8, 16 and 32 seconds while keeping the device awake (=use battery power) and try again to connect. If this fails, FairEmail will schedule an alarm to retry after 15, 30 and 60 minutes and let the device sleep (=no battery usage).
 
-Between connectivity changes there is a wait of 90 seconds to give the email server the opportunity to discover the old connection is broken. This is necessary because the internet connection of a mobile device is often lost abruptly and to prevent the problem described in [this FAQ](#user-content-faq23).
-
 Note that [Android doze mode](https://developer.android.com/training/monitoring-device-state/doze-standby) does not allow to wake the device earlier than after 15 minutes.
 
 *Force sync* in the three-dots menu of the unified inbox can be used to let FairEmail attempt to reconnect without waiting.
@@ -2558,7 +2555,7 @@ Version 1.1082 added a local trash folder. Note that trashing a message will per
 
 To record voice notes you can press this icon in the bottom action bar of the message composer:
 
-![Image externe](https://github.com/M66B/FairEmail/blob/master/images/baseline_record_voice_over_black_48dp.png)
+![External image](https://github.com/M66B/FairEmail/blob/master/images/baseline_record_voice_over_black_48dp.png)
 
 This requires a compatible audio recorder app to be installed. In particular [this common intent](https://developer.android.com/reference/android/provider/MediaStore.Audio.Media.html#RECORD_SOUND_ACTION) needs to be supported.
 
@@ -2762,53 +2759,55 @@ Tracking images will be disabled only if the corresponding main 'disable' option
 
 Tracking images will not be recognized when the domain is classified as '*Content*', see [here](https://disconnect.me/trackerprotection#trackers-we-dont-block) for more information.
 
-Cette commande peut être envoyée à FairEmail depuis une application d'automatisation pour mettre à jour les listes de protection :
+This command can be sent to FairEmail from an automation app to update the protection lists:
 
 ```
 (adb shell) am startservice -a eu.faircode.email.DISCONNECT.ME
 ```
 
-Mettre à jour une fois par semaine sera probablement suffisant, veuillez consulter [ici](https://github.com/disconnectme/disconnect-tracking-protection/commits/master) pour la liste des modifications récentes.
+Updating once a week will probably be sufficient, please see [here](https://github.com/disconnectme/disconnect-tracking-protection/commits/master) for recent lists changes.
 
 <br />
 
 <a name="faq160"></a>
-**(160) Pouvez-vous ajouter une suppression permanente des messages sans confirmation ?**
+**(160) Can you add permanent deletion of messages without confirmation?**
+
+Permanent deletion means that messages will *irreversibly* be lost, and to prevent this from happening accidentally, this always needs to be confirmed. Even with a confirmation, some very angry people who lost some of their messages through their own fault contacted me, which was a rather unpleasant experience :-(
 
-La suppression permanente signifie que les messages seront *irréversiblement* perdus, et pour éviter que cela ne se produise accidentellement, cela doit toujours être confirmé. Même avec confirmation, certaines personnes très en colère qui ont perdu certains de leurs messages par leur propre faute m'ont contacté, qui a été une expérience plutôt désagréable :-(
+Advanced: the IMAP delete flag in combination with the EXPUNGE command is not supportable because both email servers and not all people can handle this, risking unexpected loss of messages. A complicating factor is that not all email servers support [UID EXPUNGE](https://tools.ietf.org/html/rfc4315).
 
 <br />
 
 <a name="faq161"></a>
-**(161) Peux-tu ajouter un paramètre pour changer la couleur primaire et d'accentuation ?***
+**(161) Can you add a setting to change the primary and accent color?***
 
-Si je le pouvais, j'ajouterais un paramètre pour sélectionner la couleur primaire et de l'accent tout de suite, mais malheureusement les thèmes Android sont fixes, voir par exemple [ici](https://stackoverflow.com/a/26511725/1794097), donc ce n'est pas possible.
+If I could, I would add a setting to select the primary and accent color right away, but unfortunately Android themes are fixed, see for example [here](https://stackoverflow.com/a/26511725/1794097), so this is not possible.
 
 <br />
 
 
 ## Obtenir de l'aide
 
-FairEmail est pris en charge uniquement sur les smartphones, tablettes et ChromeOS.
+FairEmail is supported on smartphones, tablets and ChromeOS only.
 
-Seules la dernière version du Play Store et la dernière version de GitHub sont prises en charge. La version F-Droid n'est prise en charge que si le numéro de version est le même que le numéro de version de la dernière version de GitHub. Cela signifie également que la rétrogradation n'est pas prise en charge.
+Only the latest Play store version and latest GitHub release are supported. The F-Droid build is supported only if the version number is the same as the version number of the latest GitHub release. This also means that downgrading is not supported.
 
-Il n'y a pas de support sur des choses qui ne sont pas directement liées à FairEmail.
+There is no support on things that are not directly related to FairEmail.
 
-Il n'y a aucun soutien pour construire et développer les choses par vous-même.
+There is no support on building and developing things by yourself.
 
-Les fonctionnalités demandées doivent :
+Requested features should:
 
 * être utile à la plupart des gens
 * ne pas compliquer l'utilisation de FairEmail
 * s'inscrire dans la philosophie de FairEmail (orienté vers la confidentialité, centré sur la sécurité)
 * se conformer aux normes communes (IMAP, SMTP, etc.)
 
-Les caractéristiques qui ne satisfont pas à ces exigences seront probablement rejetées. Il s'agit également de maintenir la maintenance et le soutien à long terme réalisable.
+Features not fulfilling these requirements will likely be rejected. This is also to keep maintenance and support in the long term feasible.
 
-Si vous avez une question, si vous voulez demander une fonctionnalité ou signaler un bogue, veuillez utiliser [ce formulaire](https://contact.faircode.eu/?product=fairemailsupport).
+If you have a question, want to request a feature or report a bug, please use [this form](https://contact.faircode.eu/?product=fairemailsupport).
 
-Les "issues"/tickets GitHub sont désactivés en raison d'un usage abusif fréquent.
+GitHub issues are disabled due to frequent misusage.
 
 <br />
 
diff --git a/docs/FAQ-fr-rFR.md b/docs/FAQ-fr-rFR.md
index 536b01b419..5954e307f1 100644
--- a/docs/FAQ-fr-rFR.md
+++ b/docs/FAQ-fr-rFR.md
@@ -78,6 +78,7 @@ Questions liées:
 * Un aperçu d'un message texte n'apparaît pas (toujours) sur les montres Samsung car [setLocalOnly](https://developer.android.com/reference/androidx/core/app/NotificationCompat.Builder.html#setLocalOnly(boolean)) semble être ignoré. Les textes de prévisualisation des messages sont censés être affichés correctement sur les objets connectés Pebble 2, Fitbit Charge 3, Mi band 3 et Xiaomi Amazfit BIP. Voir aussi [cette FAQ](#user-content-faq126).
 * Un [bug sur Android 6.0](https://issuetracker.google.com/issues/37068143) provoque un plantage *... Invalid offset: ... Valid range is ...* lorsque du texte est sélectionné et en tapotant à côté de ce dernier. Ce bogue a été corrigé dans Android 6.0.1.
 * Les liens internes (ancres) ne fonctionnent pas, car les messages originaux sont affichés dans un composant WebView intégré à une vue défilante (la liste de la conversation). Il s'agit d'une limitation d'Android qui ne peut pas être corrigée ou contournée.
+* Language detection [is not working anymore](https://issuetracker.google.com/issues/173337263) on Pixel devices with (upgraded to?) Android 11
 
 ## Fonctionnalités prévues
 
@@ -861,7 +862,7 @@ The error *... Connection refused ...* means that the email server or something
 
 The error *... Network unreachable ...* means that the email server was not reachable via the current internet connection, for example because internet traffic is restricted to local traffic only.
 
-The error *... Host is unresolved ...* or "*... Unable to resolve host ...* means that the address of the email server could not be resolved. This might be caused by ad blocking or an unreachable or not properly working [DNS](https://en.wikipedia.org/wiki/Domain_Name_System) server.
+The error *... Host is unresolved ...*, *... Unable to resolve host ...* or *... No address associated with hostname ...* means that the address of the email server could not be resolved into an IP address. This might be caused by a VPN, ad blocking or an unreachable or not properly working (local) [DNS](https://en.wikipedia.org/wiki/Domain_Name_System) server.
 
 The error *... Software caused connection abort ...* means that the email server or something between FairEmail and the email server actively terminated an existing connection. This can for example happen when connectivity was abruptly lost. A typical example is turning on flight mode.
 
@@ -2162,14 +2163,12 @@ Disabling *Partial fetch* will result in more memory usage.
 <a name="faq111"></a>
 **(111) Is OAuth supported?**
 
-OAuth for Gmail is supported via the quick setup wizard. The Android account manager will be used to fetch and refresh OAuth tokens for selected on-device accounts. OAuth for non on-device accounts is not supported because Google requires a [yearly security audit](https://support.google.com/cloud/answer/9110914) ($15,000 to $75,000) for this.
+OAuth for Gmail is supported via the quick setup wizard. The Android account manager will be used to fetch and refresh OAuth tokens for selected on-device accounts. OAuth for non on-device accounts is not supported because Google requires a [yearly security audit](https://support.google.com/cloud/answer/9110914) ($15,000 to $75,000) for this. You can read more about this [here](https://www.theregister.com/2019/02/11/google_gmail_developer/).
 
-OAuth for Yandex is supported via the quick setup wizard.
+OAuth for Yandex and Yahoo is supported via the quick setup wizard.
 
 OAuth for Office 365 accounts is supported, but Microsoft does not offer OAuth for Outlook, Live and Hotmail accounts (yet?).
 
-OAuth access for Yahoo was requested, but Yahoo never responded to the request. OAuth for AOL [was deactivated](https://www.programmableweb.com/api/aol-open-auth) by AOL. Verizon owns both AOL and Yahoo, collectively named [Oath inc](https://en.wikipedia.org/wiki/Verizon_Media). So, it is reasonable to assume that OAuth is not supported by Yahoo anymore too.
-
 <br />
 
 <a name="faq112"></a>
@@ -2302,8 +2301,6 @@ FairEmail groups messages based on the standard *Message-ID*, *In-Reply-To* and
 
 When FairEmail cannot connect to an email server to receive messages, for example when the internet connection is bad or a firewall or a VPN is blocking the connection, FairEmail will wait 8, 16 and 32 seconds while keeping the device awake (=use battery power) and try again to connect. If this fails, FairEmail will schedule an alarm to retry after 15, 30 and 60 minutes and let the device sleep (=no battery usage).
 
-Between connectivity changes there is a wait of 90 seconds to give the email server the opportunity to discover the old connection is broken. This is necessary because the internet connection of a mobile device is often lost abruptly and to prevent the problem described in [this FAQ](#user-content-faq23).
-
 Note that [Android doze mode](https://developer.android.com/training/monitoring-device-state/doze-standby) does not allow to wake the device earlier than after 15 minutes.
 
 *Force sync* in the three-dots menu of the unified inbox can be used to let FairEmail attempt to reconnect without waiting.
@@ -2558,7 +2555,7 @@ Version 1.1082 added a local trash folder. Note that trashing a message will per
 
 To record voice notes you can press this icon in the bottom action bar of the message composer:
 
-![Image externe](https://github.com/M66B/FairEmail/blob/master/images/baseline_record_voice_over_black_48dp.png)
+![External image](https://github.com/M66B/FairEmail/blob/master/images/baseline_record_voice_over_black_48dp.png)
 
 This requires a compatible audio recorder app to be installed. In particular [this common intent](https://developer.android.com/reference/android/provider/MediaStore.Audio.Media.html#RECORD_SOUND_ACTION) needs to be supported.
 
@@ -2762,53 +2759,55 @@ Tracking images will be disabled only if the corresponding main 'disable' option
 
 Tracking images will not be recognized when the domain is classified as '*Content*', see [here](https://disconnect.me/trackerprotection#trackers-we-dont-block) for more information.
 
-Cette commande peut être envoyée à FairEmail depuis une application d'automatisation pour mettre à jour les listes de protection :
+This command can be sent to FairEmail from an automation app to update the protection lists:
 
 ```
 (adb shell) am startservice -a eu.faircode.email.DISCONNECT.ME
 ```
 
-Mettre à jour une fois par semaine sera probablement suffisant, veuillez consulter [ici](https://github.com/disconnectme/disconnect-tracking-protection/commits/master) pour la liste des modifications récentes.
+Updating once a week will probably be sufficient, please see [here](https://github.com/disconnectme/disconnect-tracking-protection/commits/master) for recent lists changes.
 
 <br />
 
 <a name="faq160"></a>
-**(160) Pouvez-vous ajouter une suppression permanente des messages sans confirmation ?**
+**(160) Can you add permanent deletion of messages without confirmation?**
+
+Permanent deletion means that messages will *irreversibly* be lost, and to prevent this from happening accidentally, this always needs to be confirmed. Even with a confirmation, some very angry people who lost some of their messages through their own fault contacted me, which was a rather unpleasant experience :-(
 
-La suppression permanente signifie que les messages seront *irréversiblement* perdus, et pour éviter que cela ne se produise accidentellement, cela doit toujours être confirmé. Même avec confirmation, certaines personnes très en colère qui ont perdu certains de leurs messages par leur propre faute m'ont contacté, qui a été une expérience plutôt désagréable :-(
+Advanced: the IMAP delete flag in combination with the EXPUNGE command is not supportable because both email servers and not all people can handle this, risking unexpected loss of messages. A complicating factor is that not all email servers support [UID EXPUNGE](https://tools.ietf.org/html/rfc4315).
 
 <br />
 
 <a name="faq161"></a>
-**(161) Peux-tu ajouter un paramètre pour changer la couleur primaire et d'accentuation ?***
+**(161) Can you add a setting to change the primary and accent color?***
 
-Si je le pouvais, j'ajouterais un paramètre pour sélectionner la couleur primaire et de l'accent tout de suite, mais malheureusement les thèmes Android sont fixes, voir par exemple [ici](https://stackoverflow.com/a/26511725/1794097), donc ce n'est pas possible.
+If I could, I would add a setting to select the primary and accent color right away, but unfortunately Android themes are fixed, see for example [here](https://stackoverflow.com/a/26511725/1794097), so this is not possible.
 
 <br />
 
 
 ## Obtenir de l'aide
 
-FairEmail est pris en charge uniquement sur les smartphones, tablettes et ChromeOS.
+FairEmail is supported on smartphones, tablets and ChromeOS only.
 
-Seules la dernière version du Play Store et la dernière version de GitHub sont prises en charge. La version F-Droid n'est prise en charge que si le numéro de version est le même que le numéro de version de la dernière version de GitHub. Cela signifie également que la rétrogradation n'est pas prise en charge.
+Only the latest Play store version and latest GitHub release are supported. The F-Droid build is supported only if the version number is the same as the version number of the latest GitHub release. This also means that downgrading is not supported.
 
-Il n'y a pas de support sur des choses qui ne sont pas directement liées à FairEmail.
+There is no support on things that are not directly related to FairEmail.
 
-Il n'y a aucun soutien pour construire et développer les choses par vous-même.
+There is no support on building and developing things by yourself.
 
-Les fonctionnalités demandées doivent :
+Requested features should:
 
 * être utile à la plupart des gens
 * ne pas compliquer l'utilisation de FairEmail
 * s'inscrire dans la philosophie de FairEmail (orienté vers la confidentialité, centré sur la sécurité)
 * se conformer aux normes communes (IMAP, SMTP, etc.)
 
-Les caractéristiques qui ne satisfont pas à ces exigences seront probablement rejetées. Il s'agit également de maintenir la maintenance et le soutien à long terme réalisable.
+Features not fulfilling these requirements will likely be rejected. This is also to keep maintenance and support in the long term feasible.
 
-Si vous avez une question, si vous voulez demander une fonctionnalité ou signaler un bogue, veuillez utiliser [ce formulaire](https://contact.faircode.eu/?product=fairemailsupport).
+If you have a question, want to request a feature or report a bug, please use [this form](https://contact.faircode.eu/?product=fairemailsupport).
 
-Les "issues"/tickets GitHub sont désactivés en raison d'un usage abusif fréquent.
+GitHub issues are disabled due to frequent misusage.
 
 <br />
 
diff --git a/docs/FAQ-fy-rNL.md b/docs/FAQ-fy-rNL.md
index 7b7b451250..a593607a58 100644
--- a/docs/FAQ-fy-rNL.md
+++ b/docs/FAQ-fy-rNL.md
@@ -78,6 +78,7 @@ Related questions:
 * A preview of a message text doesn't (always) appear on Samsung watches because [setLocalOnly](https://developer.android.com/reference/androidx/core/app/NotificationCompat.Builder.html#setLocalOnly(boolean)) seem to be ignored. Message preview texts are known to be displayed correctly on Pebble 2, Fitbit Charge 3, Mi band 3, and Xiaomi Amazfit BIP wearables. See also [this FAQ](#user-content-faq126).
 * A [bug in Android 6.0](https://issuetracker.google.com/issues/37068143) causes a crash with *... Invalid offset: ... Valid range is ...* when text is selected and tapping outside of the selected text. This bug has been fixed in Android 6.0.1.
 * Internal (anchor) links will not work because original messages are shown in an embedded WebView in a scrolling view (the conversation list). This is an Android limitation which cannot be fixed or worked around.
+* Language detection [is not working anymore](https://issuetracker.google.com/issues/173337263) on Pixel devices with (upgraded to?) Android 11
 
 ## Planned features
 
@@ -861,7 +862,7 @@ The error *... Connection refused ...* means that the email server or something
 
 The error *... Network unreachable ...* means that the email server was not reachable via the current internet connection, for example because internet traffic is restricted to local traffic only.
 
-The error *... Host is unresolved ...* or "*... Unable to resolve host ...* means that the address of the email server could not be resolved. This might be caused by ad blocking or an unreachable or not properly working [DNS](https://en.wikipedia.org/wiki/Domain_Name_System) server.
+The error *... Host is unresolved ...*, *... Unable to resolve host ...* or *... No address associated with hostname ...* means that the address of the email server could not be resolved into an IP address. This might be caused by a VPN, ad blocking or an unreachable or not properly working (local) [DNS](https://en.wikipedia.org/wiki/Domain_Name_System) server.
 
 The error *... Software caused connection abort ...* means that the email server or something between FairEmail and the email server actively terminated an existing connection. This can for example happen when connectivity was abruptly lost. A typical example is turning on flight mode.
 
@@ -2162,14 +2163,12 @@ Disabling *Partial fetch* will result in more memory usage.
 <a name="faq111"></a>
 **(111) Is OAuth supported?**
 
-OAuth for Gmail is supported via the quick setup wizard. The Android account manager will be used to fetch and refresh OAuth tokens for selected on-device accounts. OAuth for non on-device accounts is not supported because Google requires a [yearly security audit](https://support.google.com/cloud/answer/9110914) ($15,000 to $75,000) for this.
+OAuth for Gmail is supported via the quick setup wizard. The Android account manager will be used to fetch and refresh OAuth tokens for selected on-device accounts. OAuth for non on-device accounts is not supported because Google requires a [yearly security audit](https://support.google.com/cloud/answer/9110914) ($15,000 to $75,000) for this. You can read more about this [here](https://www.theregister.com/2019/02/11/google_gmail_developer/).
 
-OAuth for Yandex is supported via the quick setup wizard.
+OAuth for Yandex and Yahoo is supported via the quick setup wizard.
 
 OAuth for Office 365 accounts is supported, but Microsoft does not offer OAuth for Outlook, Live and Hotmail accounts (yet?).
 
-OAuth access for Yahoo was requested, but Yahoo never responded to the request. OAuth for AOL [was deactivated](https://www.programmableweb.com/api/aol-open-auth) by AOL. Verizon owns both AOL and Yahoo, collectively named [Oath inc](https://en.wikipedia.org/wiki/Verizon_Media). So, it is reasonable to assume that OAuth is not supported by Yahoo anymore too.
-
 <br />
 
 <a name="faq112"></a>
@@ -2302,8 +2301,6 @@ FairEmail groups messages based on the standard *Message-ID*, *In-Reply-To* and
 
 When FairEmail cannot connect to an email server to receive messages, for example when the internet connection is bad or a firewall or a VPN is blocking the connection, FairEmail will wait 8, 16 and 32 seconds while keeping the device awake (=use battery power) and try again to connect. If this fails, FairEmail will schedule an alarm to retry after 15, 30 and 60 minutes and let the device sleep (=no battery usage).
 
-Between connectivity changes there is a wait of 90 seconds to give the email server the opportunity to discover the old connection is broken. This is necessary because the internet connection of a mobile device is often lost abruptly and to prevent the problem described in [this FAQ](#user-content-faq23).
-
 Note that [Android doze mode](https://developer.android.com/training/monitoring-device-state/doze-standby) does not allow to wake the device earlier than after 15 minutes.
 
 *Force sync* in the three-dots menu of the unified inbox can be used to let FairEmail attempt to reconnect without waiting.
@@ -2777,6 +2774,8 @@ Updating once a week will probably be sufficient, please see [here](https://gith
 
 Permanent deletion means that messages will *irreversibly* be lost, and to prevent this from happening accidentally, this always needs to be confirmed. Even with a confirmation, some very angry people who lost some of their messages through their own fault contacted me, which was a rather unpleasant experience :-(
 
+Advanced: the IMAP delete flag in combination with the EXPUNGE command is not supportable because both email servers and not all people can handle this, risking unexpected loss of messages. A complicating factor is that not all email servers support [UID EXPUNGE](https://tools.ietf.org/html/rfc4315).
+
 <br />
 
 <a name="faq161"></a>
diff --git a/docs/FAQ-gl-rES.md b/docs/FAQ-gl-rES.md
index 880729571b..5cdc93586f 100644
--- a/docs/FAQ-gl-rES.md
+++ b/docs/FAQ-gl-rES.md
@@ -78,6 +78,7 @@ Preguntas relacionadas:
 * A preview of a message text doesn't (always) appear on Samsung watches because [setLocalOnly](https://developer.android.com/reference/androidx/core/app/NotificationCompat.Builder.html#setLocalOnly(boolean)) seem to be ignored. Message preview texts are known to be displayed correctly on Pebble 2, Fitbit Charge 3, Mi band 3, and Xiaomi Amazfit BIP wearables. See also [this FAQ](#user-content-faq126).
 * A [bug in Android 6.0](https://issuetracker.google.com/issues/37068143) causes a crash with *... Invalid offset: ... Valid range is ...* when text is selected and tapping outside of the selected text. This bug has been fixed in Android 6.0.1.
 * Internal (anchor) links will not work because original messages are shown in an embedded WebView in a scrolling view (the conversation list). This is an Android limitation which cannot be fixed or worked around.
+* Language detection [is not working anymore](https://issuetracker.google.com/issues/173337263) on Pixel devices with (upgraded to?) Android 11
 
 ## Planned features
 
@@ -861,7 +862,7 @@ The error *... Connection refused ...* means that the email server or something
 
 The error *... Network unreachable ...* means that the email server was not reachable via the current internet connection, for example because internet traffic is restricted to local traffic only.
 
-The error *... Host is unresolved ...* or "*... Unable to resolve host ...* means that the address of the email server could not be resolved. This might be caused by ad blocking or an unreachable or not properly working [DNS](https://en.wikipedia.org/wiki/Domain_Name_System) server.
+The error *... Host is unresolved ...*, *... Unable to resolve host ...* or *... No address associated with hostname ...* means that the address of the email server could not be resolved into an IP address. This might be caused by a VPN, ad blocking or an unreachable or not properly working (local) [DNS](https://en.wikipedia.org/wiki/Domain_Name_System) server.
 
 The error *... Software caused connection abort ...* means that the email server or something between FairEmail and the email server actively terminated an existing connection. This can for example happen when connectivity was abruptly lost. A typical example is turning on flight mode.
 
@@ -2162,14 +2163,12 @@ Disabling *Partial fetch* will result in more memory usage.
 <a name="faq111"></a>
 **(111) Is OAuth supported?**
 
-OAuth for Gmail is supported via the quick setup wizard. The Android account manager will be used to fetch and refresh OAuth tokens for selected on-device accounts. OAuth for non on-device accounts is not supported because Google requires a [yearly security audit](https://support.google.com/cloud/answer/9110914) ($15,000 to $75,000) for this.
+OAuth for Gmail is supported via the quick setup wizard. The Android account manager will be used to fetch and refresh OAuth tokens for selected on-device accounts. OAuth for non on-device accounts is not supported because Google requires a [yearly security audit](https://support.google.com/cloud/answer/9110914) ($15,000 to $75,000) for this. You can read more about this [here](https://www.theregister.com/2019/02/11/google_gmail_developer/).
 
-OAuth for Yandex is supported via the quick setup wizard.
+OAuth for Yandex and Yahoo is supported via the quick setup wizard.
 
 OAuth for Office 365 accounts is supported, but Microsoft does not offer OAuth for Outlook, Live and Hotmail accounts (yet?).
 
-OAuth access for Yahoo was requested, but Yahoo never responded to the request. OAuth for AOL [was deactivated](https://www.programmableweb.com/api/aol-open-auth) by AOL. Verizon owns both AOL and Yahoo, collectively named [Oath inc](https://en.wikipedia.org/wiki/Verizon_Media). So, it is reasonable to assume that OAuth is not supported by Yahoo anymore too.
-
 <br />
 
 <a name="faq112"></a>
@@ -2302,8 +2301,6 @@ FairEmail groups messages based on the standard *Message-ID*, *In-Reply-To* and
 
 When FairEmail cannot connect to an email server to receive messages, for example when the internet connection is bad or a firewall or a VPN is blocking the connection, FairEmail will wait 8, 16 and 32 seconds while keeping the device awake (=use battery power) and try again to connect. If this fails, FairEmail will schedule an alarm to retry after 15, 30 and 60 minutes and let the device sleep (=no battery usage).
 
-Between connectivity changes there is a wait of 90 seconds to give the email server the opportunity to discover the old connection is broken. This is necessary because the internet connection of a mobile device is often lost abruptly and to prevent the problem described in [this FAQ](#user-content-faq23).
-
 Note that [Android doze mode](https://developer.android.com/training/monitoring-device-state/doze-standby) does not allow to wake the device earlier than after 15 minutes.
 
 *Force sync* in the three-dots menu of the unified inbox can be used to let FairEmail attempt to reconnect without waiting.
@@ -2777,6 +2774,8 @@ Updating once a week will probably be sufficient, please see [here](https://gith
 
 Permanent deletion means that messages will *irreversibly* be lost, and to prevent this from happening accidentally, this always needs to be confirmed. Even with a confirmation, some very angry people who lost some of their messages through their own fault contacted me, which was a rather unpleasant experience :-(
 
+Advanced: the IMAP delete flag in combination with the EXPUNGE command is not supportable because both email servers and not all people can handle this, risking unexpected loss of messages. A complicating factor is that not all email servers support [UID EXPUNGE](https://tools.ietf.org/html/rfc4315).
+
 <br />
 
 <a name="faq161"></a>
diff --git a/docs/FAQ-hi-rIN.md b/docs/FAQ-hi-rIN.md
index 7b7b451250..a593607a58 100644
--- a/docs/FAQ-hi-rIN.md
+++ b/docs/FAQ-hi-rIN.md
@@ -78,6 +78,7 @@ Related questions:
 * A preview of a message text doesn't (always) appear on Samsung watches because [setLocalOnly](https://developer.android.com/reference/androidx/core/app/NotificationCompat.Builder.html#setLocalOnly(boolean)) seem to be ignored. Message preview texts are known to be displayed correctly on Pebble 2, Fitbit Charge 3, Mi band 3, and Xiaomi Amazfit BIP wearables. See also [this FAQ](#user-content-faq126).
 * A [bug in Android 6.0](https://issuetracker.google.com/issues/37068143) causes a crash with *... Invalid offset: ... Valid range is ...* when text is selected and tapping outside of the selected text. This bug has been fixed in Android 6.0.1.
 * Internal (anchor) links will not work because original messages are shown in an embedded WebView in a scrolling view (the conversation list). This is an Android limitation which cannot be fixed or worked around.
+* Language detection [is not working anymore](https://issuetracker.google.com/issues/173337263) on Pixel devices with (upgraded to?) Android 11
 
 ## Planned features
 
@@ -861,7 +862,7 @@ The error *... Connection refused ...* means that the email server or something
 
 The error *... Network unreachable ...* means that the email server was not reachable via the current internet connection, for example because internet traffic is restricted to local traffic only.
 
-The error *... Host is unresolved ...* or "*... Unable to resolve host ...* means that the address of the email server could not be resolved. This might be caused by ad blocking or an unreachable or not properly working [DNS](https://en.wikipedia.org/wiki/Domain_Name_System) server.
+The error *... Host is unresolved ...*, *... Unable to resolve host ...* or *... No address associated with hostname ...* means that the address of the email server could not be resolved into an IP address. This might be caused by a VPN, ad blocking or an unreachable or not properly working (local) [DNS](https://en.wikipedia.org/wiki/Domain_Name_System) server.
 
 The error *... Software caused connection abort ...* means that the email server or something between FairEmail and the email server actively terminated an existing connection. This can for example happen when connectivity was abruptly lost. A typical example is turning on flight mode.
 
@@ -2162,14 +2163,12 @@ Disabling *Partial fetch* will result in more memory usage.
 <a name="faq111"></a>
 **(111) Is OAuth supported?**
 
-OAuth for Gmail is supported via the quick setup wizard. The Android account manager will be used to fetch and refresh OAuth tokens for selected on-device accounts. OAuth for non on-device accounts is not supported because Google requires a [yearly security audit](https://support.google.com/cloud/answer/9110914) ($15,000 to $75,000) for this.
+OAuth for Gmail is supported via the quick setup wizard. The Android account manager will be used to fetch and refresh OAuth tokens for selected on-device accounts. OAuth for non on-device accounts is not supported because Google requires a [yearly security audit](https://support.google.com/cloud/answer/9110914) ($15,000 to $75,000) for this. You can read more about this [here](https://www.theregister.com/2019/02/11/google_gmail_developer/).
 
-OAuth for Yandex is supported via the quick setup wizard.
+OAuth for Yandex and Yahoo is supported via the quick setup wizard.
 
 OAuth for Office 365 accounts is supported, but Microsoft does not offer OAuth for Outlook, Live and Hotmail accounts (yet?).
 
-OAuth access for Yahoo was requested, but Yahoo never responded to the request. OAuth for AOL [was deactivated](https://www.programmableweb.com/api/aol-open-auth) by AOL. Verizon owns both AOL and Yahoo, collectively named [Oath inc](https://en.wikipedia.org/wiki/Verizon_Media). So, it is reasonable to assume that OAuth is not supported by Yahoo anymore too.
-
 <br />
 
 <a name="faq112"></a>
@@ -2302,8 +2301,6 @@ FairEmail groups messages based on the standard *Message-ID*, *In-Reply-To* and
 
 When FairEmail cannot connect to an email server to receive messages, for example when the internet connection is bad or a firewall or a VPN is blocking the connection, FairEmail will wait 8, 16 and 32 seconds while keeping the device awake (=use battery power) and try again to connect. If this fails, FairEmail will schedule an alarm to retry after 15, 30 and 60 minutes and let the device sleep (=no battery usage).
 
-Between connectivity changes there is a wait of 90 seconds to give the email server the opportunity to discover the old connection is broken. This is necessary because the internet connection of a mobile device is often lost abruptly and to prevent the problem described in [this FAQ](#user-content-faq23).
-
 Note that [Android doze mode](https://developer.android.com/training/monitoring-device-state/doze-standby) does not allow to wake the device earlier than after 15 minutes.
 
 *Force sync* in the three-dots menu of the unified inbox can be used to let FairEmail attempt to reconnect without waiting.
@@ -2777,6 +2774,8 @@ Updating once a week will probably be sufficient, please see [here](https://gith
 
 Permanent deletion means that messages will *irreversibly* be lost, and to prevent this from happening accidentally, this always needs to be confirmed. Even with a confirmation, some very angry people who lost some of their messages through their own fault contacted me, which was a rather unpleasant experience :-(
 
+Advanced: the IMAP delete flag in combination with the EXPUNGE command is not supportable because both email servers and not all people can handle this, risking unexpected loss of messages. A complicating factor is that not all email servers support [UID EXPUNGE](https://tools.ietf.org/html/rfc4315).
+
 <br />
 
 <a name="faq161"></a>
diff --git a/docs/FAQ-hr-rHR.md b/docs/FAQ-hr-rHR.md
index 7b7b451250..a593607a58 100644
--- a/docs/FAQ-hr-rHR.md
+++ b/docs/FAQ-hr-rHR.md
@@ -78,6 +78,7 @@ Related questions:
 * A preview of a message text doesn't (always) appear on Samsung watches because [setLocalOnly](https://developer.android.com/reference/androidx/core/app/NotificationCompat.Builder.html#setLocalOnly(boolean)) seem to be ignored. Message preview texts are known to be displayed correctly on Pebble 2, Fitbit Charge 3, Mi band 3, and Xiaomi Amazfit BIP wearables. See also [this FAQ](#user-content-faq126).
 * A [bug in Android 6.0](https://issuetracker.google.com/issues/37068143) causes a crash with *... Invalid offset: ... Valid range is ...* when text is selected and tapping outside of the selected text. This bug has been fixed in Android 6.0.1.
 * Internal (anchor) links will not work because original messages are shown in an embedded WebView in a scrolling view (the conversation list). This is an Android limitation which cannot be fixed or worked around.
+* Language detection [is not working anymore](https://issuetracker.google.com/issues/173337263) on Pixel devices with (upgraded to?) Android 11
 
 ## Planned features
 
@@ -861,7 +862,7 @@ The error *... Connection refused ...* means that the email server or something
 
 The error *... Network unreachable ...* means that the email server was not reachable via the current internet connection, for example because internet traffic is restricted to local traffic only.
 
-The error *... Host is unresolved ...* or "*... Unable to resolve host ...* means that the address of the email server could not be resolved. This might be caused by ad blocking or an unreachable or not properly working [DNS](https://en.wikipedia.org/wiki/Domain_Name_System) server.
+The error *... Host is unresolved ...*, *... Unable to resolve host ...* or *... No address associated with hostname ...* means that the address of the email server could not be resolved into an IP address. This might be caused by a VPN, ad blocking or an unreachable or not properly working (local) [DNS](https://en.wikipedia.org/wiki/Domain_Name_System) server.
 
 The error *... Software caused connection abort ...* means that the email server or something between FairEmail and the email server actively terminated an existing connection. This can for example happen when connectivity was abruptly lost. A typical example is turning on flight mode.
 
@@ -2162,14 +2163,12 @@ Disabling *Partial fetch* will result in more memory usage.
 <a name="faq111"></a>
 **(111) Is OAuth supported?**
 
-OAuth for Gmail is supported via the quick setup wizard. The Android account manager will be used to fetch and refresh OAuth tokens for selected on-device accounts. OAuth for non on-device accounts is not supported because Google requires a [yearly security audit](https://support.google.com/cloud/answer/9110914) ($15,000 to $75,000) for this.
+OAuth for Gmail is supported via the quick setup wizard. The Android account manager will be used to fetch and refresh OAuth tokens for selected on-device accounts. OAuth for non on-device accounts is not supported because Google requires a [yearly security audit](https://support.google.com/cloud/answer/9110914) ($15,000 to $75,000) for this. You can read more about this [here](https://www.theregister.com/2019/02/11/google_gmail_developer/).
 
-OAuth for Yandex is supported via the quick setup wizard.
+OAuth for Yandex and Yahoo is supported via the quick setup wizard.
 
 OAuth for Office 365 accounts is supported, but Microsoft does not offer OAuth for Outlook, Live and Hotmail accounts (yet?).
 
-OAuth access for Yahoo was requested, but Yahoo never responded to the request. OAuth for AOL [was deactivated](https://www.programmableweb.com/api/aol-open-auth) by AOL. Verizon owns both AOL and Yahoo, collectively named [Oath inc](https://en.wikipedia.org/wiki/Verizon_Media). So, it is reasonable to assume that OAuth is not supported by Yahoo anymore too.
-
 <br />
 
 <a name="faq112"></a>
@@ -2302,8 +2301,6 @@ FairEmail groups messages based on the standard *Message-ID*, *In-Reply-To* and
 
 When FairEmail cannot connect to an email server to receive messages, for example when the internet connection is bad or a firewall or a VPN is blocking the connection, FairEmail will wait 8, 16 and 32 seconds while keeping the device awake (=use battery power) and try again to connect. If this fails, FairEmail will schedule an alarm to retry after 15, 30 and 60 minutes and let the device sleep (=no battery usage).
 
-Between connectivity changes there is a wait of 90 seconds to give the email server the opportunity to discover the old connection is broken. This is necessary because the internet connection of a mobile device is often lost abruptly and to prevent the problem described in [this FAQ](#user-content-faq23).
-
 Note that [Android doze mode](https://developer.android.com/training/monitoring-device-state/doze-standby) does not allow to wake the device earlier than after 15 minutes.
 
 *Force sync* in the three-dots menu of the unified inbox can be used to let FairEmail attempt to reconnect without waiting.
@@ -2777,6 +2774,8 @@ Updating once a week will probably be sufficient, please see [here](https://gith
 
 Permanent deletion means that messages will *irreversibly* be lost, and to prevent this from happening accidentally, this always needs to be confirmed. Even with a confirmation, some very angry people who lost some of their messages through their own fault contacted me, which was a rather unpleasant experience :-(
 
+Advanced: the IMAP delete flag in combination with the EXPUNGE command is not supportable because both email servers and not all people can handle this, risking unexpected loss of messages. A complicating factor is that not all email servers support [UID EXPUNGE](https://tools.ietf.org/html/rfc4315).
+
 <br />
 
 <a name="faq161"></a>
diff --git a/docs/FAQ-hu-rHU.md b/docs/FAQ-hu-rHU.md
index f1c3d4bb07..8da070b612 100644
--- a/docs/FAQ-hu-rHU.md
+++ b/docs/FAQ-hu-rHU.md
@@ -78,6 +78,7 @@ Kapcsolódó kérdések:
 * A preview of a message text doesn't (always) appear on Samsung watches because [setLocalOnly](https://developer.android.com/reference/androidx/core/app/NotificationCompat.Builder.html#setLocalOnly(boolean)) seem to be ignored. Message preview texts are known to be displayed correctly on Pebble 2, Fitbit Charge 3, Mi band 3, and Xiaomi Amazfit BIP wearables. See also [this FAQ](#user-content-faq126).
 * A [bug in Android 6.0](https://issuetracker.google.com/issues/37068143) causes a crash with *... Invalid offset: ... Valid range is ...* when text is selected and tapping outside of the selected text. This bug has been fixed in Android 6.0.1.
 * Internal (anchor) links will not work because original messages are shown in an embedded WebView in a scrolling view (the conversation list). This is an Android limitation which cannot be fixed or worked around.
+* Language detection [is not working anymore](https://issuetracker.google.com/issues/173337263) on Pixel devices with (upgraded to?) Android 11
 
 ## Tervezett funkciók
 
@@ -861,7 +862,7 @@ The error *... Connection refused ...* means that the email server or something
 
 The error *... Network unreachable ...* means that the email server was not reachable via the current internet connection, for example because internet traffic is restricted to local traffic only.
 
-The error *... Host is unresolved ...* or "*... Unable to resolve host ...* means that the address of the email server could not be resolved. This might be caused by ad blocking or an unreachable or not properly working [DNS](https://en.wikipedia.org/wiki/Domain_Name_System) server.
+The error *... Host is unresolved ...*, *... Unable to resolve host ...* or *... No address associated with hostname ...* means that the address of the email server could not be resolved into an IP address. This might be caused by a VPN, ad blocking or an unreachable or not properly working (local) [DNS](https://en.wikipedia.org/wiki/Domain_Name_System) server.
 
 The error *... Software caused connection abort ...* means that the email server or something between FairEmail and the email server actively terminated an existing connection. This can for example happen when connectivity was abruptly lost. A typical example is turning on flight mode.
 
@@ -2162,14 +2163,12 @@ Disabling *Partial fetch* will result in more memory usage.
 <a name="faq111"></a>
 **(111) Is OAuth supported?**
 
-OAuth for Gmail is supported via the quick setup wizard. The Android account manager will be used to fetch and refresh OAuth tokens for selected on-device accounts. OAuth for non on-device accounts is not supported because Google requires a [yearly security audit](https://support.google.com/cloud/answer/9110914) ($15,000 to $75,000) for this.
+OAuth for Gmail is supported via the quick setup wizard. The Android account manager will be used to fetch and refresh OAuth tokens for selected on-device accounts. OAuth for non on-device accounts is not supported because Google requires a [yearly security audit](https://support.google.com/cloud/answer/9110914) ($15,000 to $75,000) for this. You can read more about this [here](https://www.theregister.com/2019/02/11/google_gmail_developer/).
 
-OAuth for Yandex is supported via the quick setup wizard.
+OAuth for Yandex and Yahoo is supported via the quick setup wizard.
 
 OAuth for Office 365 accounts is supported, but Microsoft does not offer OAuth for Outlook, Live and Hotmail accounts (yet?).
 
-OAuth access for Yahoo was requested, but Yahoo never responded to the request. OAuth for AOL [was deactivated](https://www.programmableweb.com/api/aol-open-auth) by AOL. Verizon owns both AOL and Yahoo, collectively named [Oath inc](https://en.wikipedia.org/wiki/Verizon_Media). So, it is reasonable to assume that OAuth is not supported by Yahoo anymore too.
-
 <br />
 
 <a name="faq112"></a>
@@ -2302,8 +2301,6 @@ FairEmail groups messages based on the standard *Message-ID*, *In-Reply-To* and
 
 When FairEmail cannot connect to an email server to receive messages, for example when the internet connection is bad or a firewall or a VPN is blocking the connection, FairEmail will wait 8, 16 and 32 seconds while keeping the device awake (=use battery power) and try again to connect. If this fails, FairEmail will schedule an alarm to retry after 15, 30 and 60 minutes and let the device sleep (=no battery usage).
 
-Between connectivity changes there is a wait of 90 seconds to give the email server the opportunity to discover the old connection is broken. This is necessary because the internet connection of a mobile device is often lost abruptly and to prevent the problem described in [this FAQ](#user-content-faq23).
-
 Note that [Android doze mode](https://developer.android.com/training/monitoring-device-state/doze-standby) does not allow to wake the device earlier than after 15 minutes.
 
 *Force sync* in the three-dots menu of the unified inbox can be used to let FairEmail attempt to reconnect without waiting.
@@ -2777,6 +2774,8 @@ Updating once a week will probably be sufficient, please see [here](https://gith
 
 Permanent deletion means that messages will *irreversibly* be lost, and to prevent this from happening accidentally, this always needs to be confirmed. Even with a confirmation, some very angry people who lost some of their messages through their own fault contacted me, which was a rather unpleasant experience :-(
 
+Advanced: the IMAP delete flag in combination with the EXPUNGE command is not supportable because both email servers and not all people can handle this, risking unexpected loss of messages. A complicating factor is that not all email servers support [UID EXPUNGE](https://tools.ietf.org/html/rfc4315).
+
 <br />
 
 <a name="faq161"></a>
diff --git a/docs/FAQ-in-rID.md b/docs/FAQ-in-rID.md
index 39ec04732f..9d58eb1efa 100644
--- a/docs/FAQ-in-rID.md
+++ b/docs/FAQ-in-rID.md
@@ -78,6 +78,7 @@ Pertanyaan terkait:
 * Tampilan teks pesan tidak (selalu) terlihat pada jam Samsung karena [setLocalOnly](https://developer.android.com/reference/androidx/core/app/NotificationCompat.Builder.html#setLocalOnly(boolean)) sepertinya dihindari. Tampilan teks pesan diketahui dapat ditampilkan dengan benar pada perangkat wearable Pebble 2, Fitbit Charge 3, Mi band 3, dan Xiaomi Amazfit BIP. Lihat juga [FAQ ini](#user-content-faq126).
 * [Bug idi Android 6.0](https://issuetracker.google.com/issues/37068143) menyebabkan crash dengan *... Invalid offset: ... Valid range is ...* when text is selected and tapping outside of the selected text. Bug ini telah diperbaiki dalam Android 6.0.1.
 * Internal (anchor) links will not work because original messages are shown in an embedded WebView in a scrolling view (the conversation list). Hal ini merupakan limitasi Android yang tidak dapat diperbaiki atau di buat bekerja.
+* Language detection [is not working anymore](https://issuetracker.google.com/issues/173337263) on Pixel devices with (upgraded to?) Android 11
 
 ## Fitur yang Direncanakan
 
@@ -861,7 +862,7 @@ The error *... Connection refused ...* means that the email server or something
 
 The error *... Network unreachable ...* means that the email server was not reachable via the current internet connection, for example because internet traffic is restricted to local traffic only.
 
-The error *... Host is unresolved ...* or "*... Unable to resolve host ...* means that the address of the email server could not be resolved. This might be caused by ad blocking or an unreachable or not properly working [DNS](https://en.wikipedia.org/wiki/Domain_Name_System) server.
+The error *... Host is unresolved ...*, *... Unable to resolve host ...* or *... No address associated with hostname ...* means that the address of the email server could not be resolved into an IP address. This might be caused by a VPN, ad blocking or an unreachable or not properly working (local) [DNS](https://en.wikipedia.org/wiki/Domain_Name_System) server.
 
 The error *... Software caused connection abort ...* means that the email server or something between FairEmail and the email server actively terminated an existing connection. This can for example happen when connectivity was abruptly lost. A typical example is turning on flight mode.
 
@@ -2162,14 +2163,12 @@ Disabling *Partial fetch* will result in more memory usage.
 <a name="faq111"></a>
 **(111) Is OAuth supported?**
 
-OAuth for Gmail is supported via the quick setup wizard. The Android account manager will be used to fetch and refresh OAuth tokens for selected on-device accounts. OAuth for non on-device accounts is not supported because Google requires a [yearly security audit](https://support.google.com/cloud/answer/9110914) ($15,000 to $75,000) for this.
+OAuth for Gmail is supported via the quick setup wizard. The Android account manager will be used to fetch and refresh OAuth tokens for selected on-device accounts. OAuth for non on-device accounts is not supported because Google requires a [yearly security audit](https://support.google.com/cloud/answer/9110914) ($15,000 to $75,000) for this. You can read more about this [here](https://www.theregister.com/2019/02/11/google_gmail_developer/).
 
-OAuth for Yandex is supported via the quick setup wizard.
+OAuth for Yandex and Yahoo is supported via the quick setup wizard.
 
 OAuth for Office 365 accounts is supported, but Microsoft does not offer OAuth for Outlook, Live and Hotmail accounts (yet?).
 
-OAuth access for Yahoo was requested, but Yahoo never responded to the request. OAuth for AOL [was deactivated](https://www.programmableweb.com/api/aol-open-auth) by AOL. Verizon owns both AOL and Yahoo, collectively named [Oath inc](https://en.wikipedia.org/wiki/Verizon_Media). So, it is reasonable to assume that OAuth is not supported by Yahoo anymore too.
-
 <br />
 
 <a name="faq112"></a>
@@ -2302,8 +2301,6 @@ FairEmail groups messages based on the standard *Message-ID*, *In-Reply-To* and
 
 When FairEmail cannot connect to an email server to receive messages, for example when the internet connection is bad or a firewall or a VPN is blocking the connection, FairEmail will wait 8, 16 and 32 seconds while keeping the device awake (=use battery power) and try again to connect. If this fails, FairEmail will schedule an alarm to retry after 15, 30 and 60 minutes and let the device sleep (=no battery usage).
 
-Between connectivity changes there is a wait of 90 seconds to give the email server the opportunity to discover the old connection is broken. This is necessary because the internet connection of a mobile device is often lost abruptly and to prevent the problem described in [this FAQ](#user-content-faq23).
-
 Note that [Android doze mode](https://developer.android.com/training/monitoring-device-state/doze-standby) does not allow to wake the device earlier than after 15 minutes.
 
 *Force sync* in the three-dots menu of the unified inbox can be used to let FairEmail attempt to reconnect without waiting.
@@ -2777,6 +2774,8 @@ Updating once a week will probably be sufficient, please see [here](https://gith
 
 Permanent deletion means that messages will *irreversibly* be lost, and to prevent this from happening accidentally, this always needs to be confirmed. Even with a confirmation, some very angry people who lost some of their messages through their own fault contacted me, which was a rather unpleasant experience :-(
 
+Advanced: the IMAP delete flag in combination with the EXPUNGE command is not supportable because both email servers and not all people can handle this, risking unexpected loss of messages. A complicating factor is that not all email servers support [UID EXPUNGE](https://tools.ietf.org/html/rfc4315).
+
 <br />
 
 <a name="faq161"></a>
diff --git a/docs/FAQ-it-rIT.md b/docs/FAQ-it-rIT.md
index de778e7db9..4f9b6864bd 100644
--- a/docs/FAQ-it-rIT.md
+++ b/docs/FAQ-it-rIT.md
@@ -77,7 +77,8 @@ Domande correlate:
 * Lo scorrimento verso una posizione collegata internamente nei messaggi originali non funziona. Ciò non può essere risolto perché la vista originale dei messaggi è contenuta in una vista a scorrimento.
 * Un'anteprima di un testo di un messaggio non (sempre) appare negli orologi Samsung perché [setLocalOnly](https://developer.android.com/reference/androidx/core/app/NotificationCompat.Builder.html#setLocalOnly(boolean)) sembra venga ignorato. I testi di anteprima del messaggio sono noti per essere visualizzati correttamente sugli indossabili Pebble 2, Fitbit Charge 3, Mi band 3 e Xiaomi Amazfit BIP. Vedi anche [queste domande frequenti](#user-content-faq126).
 * Un [errore in Android](https://issuetracker.google.com/issues/37068143) a volte provoca un crash con *... Spostamento non valido: ... L'intervallo valido è ... quando il testo è selezionato e tocca all'esterno del testo selezionato. Questo bug è stato risolto in Android 6.0.1.</li>
-* I collegamenti interni (ancoraggi) non funzioneranno perché i messaggi originali sono mostrati in una WebView incorporata in una vista a scorrimento (l'elenco delle conversazioni). Questa è una limitazione di Android che non può essere fissata o lavorata.</ul>
+* I collegamenti interni (ancoraggi) non funzioneranno perché i messaggi originali sono mostrati in una WebView incorporata in una vista a scorrimento (l'elenco delle conversazioni). Questa è una limitazione di Android che non può essere fissata o lavorata.
+* Language detection [is not working anymore](https://issuetracker.google.com/issues/173337263) on Pixel devices with (upgraded to?) Android 11</ul>
 
 ## Funzionalità pianificate
 
@@ -861,7 +862,7 @@ The error *... Connection refused ...* means that the email server or something
 
 The error *... Network unreachable ...* means that the email server was not reachable via the current internet connection, for example because internet traffic is restricted to local traffic only.
 
-The error *... Host is unresolved ...* or "*... Unable to resolve host ...* means that the address of the email server could not be resolved. This might be caused by ad blocking or an unreachable or not properly working [DNS](https://en.wikipedia.org/wiki/Domain_Name_System) server.
+The error *... Host is unresolved ...*, *... Unable to resolve host ...* or *... No address associated with hostname ...* means that the address of the email server could not be resolved into an IP address. This might be caused by a VPN, ad blocking or an unreachable or not properly working (local) [DNS](https://en.wikipedia.org/wiki/Domain_Name_System) server.
 
 The error *... Software caused connection abort ...* means that the email server or something between FairEmail and the email server actively terminated an existing connection. This can for example happen when connectivity was abruptly lost. A typical example is turning on flight mode.
 
@@ -2162,14 +2163,12 @@ Disabling *Partial fetch* will result in more memory usage.
 <a name="faq111"></a>
 **(111) Is OAuth supported?**
 
-OAuth for Gmail is supported via the quick setup wizard. The Android account manager will be used to fetch and refresh OAuth tokens for selected on-device accounts. OAuth for non on-device accounts is not supported because Google requires a [yearly security audit](https://support.google.com/cloud/answer/9110914) ($15,000 to $75,000) for this.
+OAuth for Gmail is supported via the quick setup wizard. The Android account manager will be used to fetch and refresh OAuth tokens for selected on-device accounts. OAuth for non on-device accounts is not supported because Google requires a [yearly security audit](https://support.google.com/cloud/answer/9110914) ($15,000 to $75,000) for this. You can read more about this [here](https://www.theregister.com/2019/02/11/google_gmail_developer/).
 
-OAuth for Yandex is supported via the quick setup wizard.
+OAuth for Yandex and Yahoo is supported via the quick setup wizard.
 
 OAuth for Office 365 accounts is supported, but Microsoft does not offer OAuth for Outlook, Live and Hotmail accounts (yet?).
 
-OAuth access for Yahoo was requested, but Yahoo never responded to the request. OAuth for AOL [was deactivated](https://www.programmableweb.com/api/aol-open-auth) by AOL. Verizon owns both AOL and Yahoo, collectively named [Oath inc](https://en.wikipedia.org/wiki/Verizon_Media). So, it is reasonable to assume that OAuth is not supported by Yahoo anymore too.
-
 <br />
 
 <a name="faq112"></a>
@@ -2302,8 +2301,6 @@ FairEmail groups messages based on the standard *Message-ID*, *In-Reply-To* and
 
 When FairEmail cannot connect to an email server to receive messages, for example when the internet connection is bad or a firewall or a VPN is blocking the connection, FairEmail will wait 8, 16 and 32 seconds while keeping the device awake (=use battery power) and try again to connect. If this fails, FairEmail will schedule an alarm to retry after 15, 30 and 60 minutes and let the device sleep (=no battery usage).
 
-Between connectivity changes there is a wait of 90 seconds to give the email server the opportunity to discover the old connection is broken. This is necessary because the internet connection of a mobile device is often lost abruptly and to prevent the problem described in [this FAQ](#user-content-faq23).
-
 Note that [Android doze mode](https://developer.android.com/training/monitoring-device-state/doze-standby) does not allow to wake the device earlier than after 15 minutes.
 
 *Force sync* in the three-dots menu of the unified inbox can be used to let FairEmail attempt to reconnect without waiting.
@@ -2777,6 +2774,8 @@ Updating once a week will probably be sufficient, please see [here](https://gith
 
 Permanent deletion means that messages will *irreversibly* be lost, and to prevent this from happening accidentally, this always needs to be confirmed. Even with a confirmation, some very angry people who lost some of their messages through their own fault contacted me, which was a rather unpleasant experience :-(
 
+Advanced: the IMAP delete flag in combination with the EXPUNGE command is not supportable because both email servers and not all people can handle this, risking unexpected loss of messages. A complicating factor is that not all email servers support [UID EXPUNGE](https://tools.ietf.org/html/rfc4315).
+
 <br />
 
 <a name="faq161"></a>
diff --git a/docs/FAQ-iw-rIL.md b/docs/FAQ-iw-rIL.md
index 7b7b451250..a593607a58 100644
--- a/docs/FAQ-iw-rIL.md
+++ b/docs/FAQ-iw-rIL.md
@@ -78,6 +78,7 @@ Related questions:
 * A preview of a message text doesn't (always) appear on Samsung watches because [setLocalOnly](https://developer.android.com/reference/androidx/core/app/NotificationCompat.Builder.html#setLocalOnly(boolean)) seem to be ignored. Message preview texts are known to be displayed correctly on Pebble 2, Fitbit Charge 3, Mi band 3, and Xiaomi Amazfit BIP wearables. See also [this FAQ](#user-content-faq126).
 * A [bug in Android 6.0](https://issuetracker.google.com/issues/37068143) causes a crash with *... Invalid offset: ... Valid range is ...* when text is selected and tapping outside of the selected text. This bug has been fixed in Android 6.0.1.
 * Internal (anchor) links will not work because original messages are shown in an embedded WebView in a scrolling view (the conversation list). This is an Android limitation which cannot be fixed or worked around.
+* Language detection [is not working anymore](https://issuetracker.google.com/issues/173337263) on Pixel devices with (upgraded to?) Android 11
 
 ## Planned features
 
@@ -861,7 +862,7 @@ The error *... Connection refused ...* means that the email server or something
 
 The error *... Network unreachable ...* means that the email server was not reachable via the current internet connection, for example because internet traffic is restricted to local traffic only.
 
-The error *... Host is unresolved ...* or "*... Unable to resolve host ...* means that the address of the email server could not be resolved. This might be caused by ad blocking or an unreachable or not properly working [DNS](https://en.wikipedia.org/wiki/Domain_Name_System) server.
+The error *... Host is unresolved ...*, *... Unable to resolve host ...* or *... No address associated with hostname ...* means that the address of the email server could not be resolved into an IP address. This might be caused by a VPN, ad blocking or an unreachable or not properly working (local) [DNS](https://en.wikipedia.org/wiki/Domain_Name_System) server.
 
 The error *... Software caused connection abort ...* means that the email server or something between FairEmail and the email server actively terminated an existing connection. This can for example happen when connectivity was abruptly lost. A typical example is turning on flight mode.
 
@@ -2162,14 +2163,12 @@ Disabling *Partial fetch* will result in more memory usage.
 <a name="faq111"></a>
 **(111) Is OAuth supported?**
 
-OAuth for Gmail is supported via the quick setup wizard. The Android account manager will be used to fetch and refresh OAuth tokens for selected on-device accounts. OAuth for non on-device accounts is not supported because Google requires a [yearly security audit](https://support.google.com/cloud/answer/9110914) ($15,000 to $75,000) for this.
+OAuth for Gmail is supported via the quick setup wizard. The Android account manager will be used to fetch and refresh OAuth tokens for selected on-device accounts. OAuth for non on-device accounts is not supported because Google requires a [yearly security audit](https://support.google.com/cloud/answer/9110914) ($15,000 to $75,000) for this. You can read more about this [here](https://www.theregister.com/2019/02/11/google_gmail_developer/).
 
-OAuth for Yandex is supported via the quick setup wizard.
+OAuth for Yandex and Yahoo is supported via the quick setup wizard.
 
 OAuth for Office 365 accounts is supported, but Microsoft does not offer OAuth for Outlook, Live and Hotmail accounts (yet?).
 
-OAuth access for Yahoo was requested, but Yahoo never responded to the request. OAuth for AOL [was deactivated](https://www.programmableweb.com/api/aol-open-auth) by AOL. Verizon owns both AOL and Yahoo, collectively named [Oath inc](https://en.wikipedia.org/wiki/Verizon_Media). So, it is reasonable to assume that OAuth is not supported by Yahoo anymore too.
-
 <br />
 
 <a name="faq112"></a>
@@ -2302,8 +2301,6 @@ FairEmail groups messages based on the standard *Message-ID*, *In-Reply-To* and
 
 When FairEmail cannot connect to an email server to receive messages, for example when the internet connection is bad or a firewall or a VPN is blocking the connection, FairEmail will wait 8, 16 and 32 seconds while keeping the device awake (=use battery power) and try again to connect. If this fails, FairEmail will schedule an alarm to retry after 15, 30 and 60 minutes and let the device sleep (=no battery usage).
 
-Between connectivity changes there is a wait of 90 seconds to give the email server the opportunity to discover the old connection is broken. This is necessary because the internet connection of a mobile device is often lost abruptly and to prevent the problem described in [this FAQ](#user-content-faq23).
-
 Note that [Android doze mode](https://developer.android.com/training/monitoring-device-state/doze-standby) does not allow to wake the device earlier than after 15 minutes.
 
 *Force sync* in the three-dots menu of the unified inbox can be used to let FairEmail attempt to reconnect without waiting.
@@ -2777,6 +2774,8 @@ Updating once a week will probably be sufficient, please see [here](https://gith
 
 Permanent deletion means that messages will *irreversibly* be lost, and to prevent this from happening accidentally, this always needs to be confirmed. Even with a confirmation, some very angry people who lost some of their messages through their own fault contacted me, which was a rather unpleasant experience :-(
 
+Advanced: the IMAP delete flag in combination with the EXPUNGE command is not supportable because both email servers and not all people can handle this, risking unexpected loss of messages. A complicating factor is that not all email servers support [UID EXPUNGE](https://tools.ietf.org/html/rfc4315).
+
 <br />
 
 <a name="faq161"></a>
diff --git a/docs/FAQ-ja-rJP.md b/docs/FAQ-ja-rJP.md
index 31877770e9..6f74f80ae6 100644
--- a/docs/FAQ-ja-rJP.md
+++ b/docs/FAQ-ja-rJP.md
@@ -78,6 +78,7 @@ Related questions:
 * A preview of a message text doesn't (always) appear on Samsung watches because [setLocalOnly](https://developer.android.com/reference/androidx/core/app/NotificationCompat.Builder.html#setLocalOnly(boolean)) seem to be ignored. Message preview texts are known to be displayed correctly on Pebble 2, Fitbit Charge 3, Mi band 3, and Xiaomi Amazfit BIP wearables. See also [this FAQ](#user-content-faq126).
 * A [bug in Android 6.0](https://issuetracker.google.com/issues/37068143) causes a crash with *... Invalid offset: ... Valid range is ...* when text is selected and tapping outside of the selected text. This bug has been fixed in Android 6.0.1.
 * Internal (anchor) links will not work because original messages are shown in an embedded WebView in a scrolling view (the conversation list). This is an Android limitation which cannot be fixed or worked around.
+* Language detection [is not working anymore](https://issuetracker.google.com/issues/173337263) on Pixel devices with (upgraded to?) Android 11
 
 ## Planned features
 
@@ -861,7 +862,7 @@ The error *... Connection refused ...* means that the email server or something
 
 The error *... Network unreachable ...* means that the email server was not reachable via the current internet connection, for example because internet traffic is restricted to local traffic only.
 
-The error *... Host is unresolved ...* or "*... Unable to resolve host ...* means that the address of the email server could not be resolved. This might be caused by ad blocking or an unreachable or not properly working [DNS](https://en.wikipedia.org/wiki/Domain_Name_System) server.
+The error *... Host is unresolved ...*, *... Unable to resolve host ...* or *... No address associated with hostname ...* means that the address of the email server could not be resolved into an IP address. This might be caused by a VPN, ad blocking or an unreachable or not properly working (local) [DNS](https://en.wikipedia.org/wiki/Domain_Name_System) server.
 
 The error *... Software caused connection abort ...* means that the email server or something between FairEmail and the email server actively terminated an existing connection. This can for example happen when connectivity was abruptly lost. A typical example is turning on flight mode.
 
@@ -2162,14 +2163,12 @@ Disabling *Partial fetch* will result in more memory usage.
 <a name="faq111"></a>
 **(111) Is OAuth supported?**
 
-OAuth for Gmail is supported via the quick setup wizard. The Android account manager will be used to fetch and refresh OAuth tokens for selected on-device accounts. OAuth for non on-device accounts is not supported because Google requires a [yearly security audit](https://support.google.com/cloud/answer/9110914) ($15,000 to $75,000) for this.
+OAuth for Gmail is supported via the quick setup wizard. The Android account manager will be used to fetch and refresh OAuth tokens for selected on-device accounts. OAuth for non on-device accounts is not supported because Google requires a [yearly security audit](https://support.google.com/cloud/answer/9110914) ($15,000 to $75,000) for this. You can read more about this [here](https://www.theregister.com/2019/02/11/google_gmail_developer/).
 
-OAuth for Yandex is supported via the quick setup wizard.
+OAuth for Yandex and Yahoo is supported via the quick setup wizard.
 
 OAuth for Office 365 accounts is supported, but Microsoft does not offer OAuth for Outlook, Live and Hotmail accounts (yet?).
 
-OAuth access for Yahoo was requested, but Yahoo never responded to the request. OAuth for AOL [was deactivated](https://www.programmableweb.com/api/aol-open-auth) by AOL. Verizon owns both AOL and Yahoo, collectively named [Oath inc](https://en.wikipedia.org/wiki/Verizon_Media). So, it is reasonable to assume that OAuth is not supported by Yahoo anymore too.
-
 <br />
 
 <a name="faq112"></a>
@@ -2302,8 +2301,6 @@ FairEmail groups messages based on the standard *Message-ID*, *In-Reply-To* and
 
 When FairEmail cannot connect to an email server to receive messages, for example when the internet connection is bad or a firewall or a VPN is blocking the connection, FairEmail will wait 8, 16 and 32 seconds while keeping the device awake (=use battery power) and try again to connect. If this fails, FairEmail will schedule an alarm to retry after 15, 30 and 60 minutes and let the device sleep (=no battery usage).
 
-Between connectivity changes there is a wait of 90 seconds to give the email server the opportunity to discover the old connection is broken. This is necessary because the internet connection of a mobile device is often lost abruptly and to prevent the problem described in [this FAQ](#user-content-faq23).
-
 Note that [Android doze mode](https://developer.android.com/training/monitoring-device-state/doze-standby) does not allow to wake the device earlier than after 15 minutes.
 
 *Force sync* in the three-dots menu of the unified inbox can be used to let FairEmail attempt to reconnect without waiting.
@@ -2777,6 +2774,8 @@ Updating once a week will probably be sufficient, please see [here](https://gith
 
 Permanent deletion means that messages will *irreversibly* be lost, and to prevent this from happening accidentally, this always needs to be confirmed. Even with a confirmation, some very angry people who lost some of their messages through their own fault contacted me, which was a rather unpleasant experience :-(
 
+Advanced: the IMAP delete flag in combination with the EXPUNGE command is not supportable because both email servers and not all people can handle this, risking unexpected loss of messages. A complicating factor is that not all email servers support [UID EXPUNGE](https://tools.ietf.org/html/rfc4315).
+
 <br />
 
 <a name="faq161"></a>
diff --git a/docs/FAQ-ka-rGE.md b/docs/FAQ-ka-rGE.md
index 7b7b451250..a593607a58 100644
--- a/docs/FAQ-ka-rGE.md
+++ b/docs/FAQ-ka-rGE.md
@@ -78,6 +78,7 @@ Related questions:
 * A preview of a message text doesn't (always) appear on Samsung watches because [setLocalOnly](https://developer.android.com/reference/androidx/core/app/NotificationCompat.Builder.html#setLocalOnly(boolean)) seem to be ignored. Message preview texts are known to be displayed correctly on Pebble 2, Fitbit Charge 3, Mi band 3, and Xiaomi Amazfit BIP wearables. See also [this FAQ](#user-content-faq126).
 * A [bug in Android 6.0](https://issuetracker.google.com/issues/37068143) causes a crash with *... Invalid offset: ... Valid range is ...* when text is selected and tapping outside of the selected text. This bug has been fixed in Android 6.0.1.
 * Internal (anchor) links will not work because original messages are shown in an embedded WebView in a scrolling view (the conversation list). This is an Android limitation which cannot be fixed or worked around.
+* Language detection [is not working anymore](https://issuetracker.google.com/issues/173337263) on Pixel devices with (upgraded to?) Android 11
 
 ## Planned features
 
@@ -861,7 +862,7 @@ The error *... Connection refused ...* means that the email server or something
 
 The error *... Network unreachable ...* means that the email server was not reachable via the current internet connection, for example because internet traffic is restricted to local traffic only.
 
-The error *... Host is unresolved ...* or "*... Unable to resolve host ...* means that the address of the email server could not be resolved. This might be caused by ad blocking or an unreachable or not properly working [DNS](https://en.wikipedia.org/wiki/Domain_Name_System) server.
+The error *... Host is unresolved ...*, *... Unable to resolve host ...* or *... No address associated with hostname ...* means that the address of the email server could not be resolved into an IP address. This might be caused by a VPN, ad blocking or an unreachable or not properly working (local) [DNS](https://en.wikipedia.org/wiki/Domain_Name_System) server.
 
 The error *... Software caused connection abort ...* means that the email server or something between FairEmail and the email server actively terminated an existing connection. This can for example happen when connectivity was abruptly lost. A typical example is turning on flight mode.
 
@@ -2162,14 +2163,12 @@ Disabling *Partial fetch* will result in more memory usage.
 <a name="faq111"></a>
 **(111) Is OAuth supported?**
 
-OAuth for Gmail is supported via the quick setup wizard. The Android account manager will be used to fetch and refresh OAuth tokens for selected on-device accounts. OAuth for non on-device accounts is not supported because Google requires a [yearly security audit](https://support.google.com/cloud/answer/9110914) ($15,000 to $75,000) for this.
+OAuth for Gmail is supported via the quick setup wizard. The Android account manager will be used to fetch and refresh OAuth tokens for selected on-device accounts. OAuth for non on-device accounts is not supported because Google requires a [yearly security audit](https://support.google.com/cloud/answer/9110914) ($15,000 to $75,000) for this. You can read more about this [here](https://www.theregister.com/2019/02/11/google_gmail_developer/).
 
-OAuth for Yandex is supported via the quick setup wizard.
+OAuth for Yandex and Yahoo is supported via the quick setup wizard.
 
 OAuth for Office 365 accounts is supported, but Microsoft does not offer OAuth for Outlook, Live and Hotmail accounts (yet?).
 
-OAuth access for Yahoo was requested, but Yahoo never responded to the request. OAuth for AOL [was deactivated](https://www.programmableweb.com/api/aol-open-auth) by AOL. Verizon owns both AOL and Yahoo, collectively named [Oath inc](https://en.wikipedia.org/wiki/Verizon_Media). So, it is reasonable to assume that OAuth is not supported by Yahoo anymore too.
-
 <br />
 
 <a name="faq112"></a>
@@ -2302,8 +2301,6 @@ FairEmail groups messages based on the standard *Message-ID*, *In-Reply-To* and
 
 When FairEmail cannot connect to an email server to receive messages, for example when the internet connection is bad or a firewall or a VPN is blocking the connection, FairEmail will wait 8, 16 and 32 seconds while keeping the device awake (=use battery power) and try again to connect. If this fails, FairEmail will schedule an alarm to retry after 15, 30 and 60 minutes and let the device sleep (=no battery usage).
 
-Between connectivity changes there is a wait of 90 seconds to give the email server the opportunity to discover the old connection is broken. This is necessary because the internet connection of a mobile device is often lost abruptly and to prevent the problem described in [this FAQ](#user-content-faq23).
-
 Note that [Android doze mode](https://developer.android.com/training/monitoring-device-state/doze-standby) does not allow to wake the device earlier than after 15 minutes.
 
 *Force sync* in the three-dots menu of the unified inbox can be used to let FairEmail attempt to reconnect without waiting.
@@ -2777,6 +2774,8 @@ Updating once a week will probably be sufficient, please see [here](https://gith
 
 Permanent deletion means that messages will *irreversibly* be lost, and to prevent this from happening accidentally, this always needs to be confirmed. Even with a confirmation, some very angry people who lost some of their messages through their own fault contacted me, which was a rather unpleasant experience :-(
 
+Advanced: the IMAP delete flag in combination with the EXPUNGE command is not supportable because both email servers and not all people can handle this, risking unexpected loss of messages. A complicating factor is that not all email servers support [UID EXPUNGE](https://tools.ietf.org/html/rfc4315).
+
 <br />
 
 <a name="faq161"></a>
diff --git a/docs/FAQ-kk-rKZ.md b/docs/FAQ-kk-rKZ.md
index 7b7b451250..a593607a58 100644
--- a/docs/FAQ-kk-rKZ.md
+++ b/docs/FAQ-kk-rKZ.md
@@ -78,6 +78,7 @@ Related questions:
 * A preview of a message text doesn't (always) appear on Samsung watches because [setLocalOnly](https://developer.android.com/reference/androidx/core/app/NotificationCompat.Builder.html#setLocalOnly(boolean)) seem to be ignored. Message preview texts are known to be displayed correctly on Pebble 2, Fitbit Charge 3, Mi band 3, and Xiaomi Amazfit BIP wearables. See also [this FAQ](#user-content-faq126).
 * A [bug in Android 6.0](https://issuetracker.google.com/issues/37068143) causes a crash with *... Invalid offset: ... Valid range is ...* when text is selected and tapping outside of the selected text. This bug has been fixed in Android 6.0.1.
 * Internal (anchor) links will not work because original messages are shown in an embedded WebView in a scrolling view (the conversation list). This is an Android limitation which cannot be fixed or worked around.
+* Language detection [is not working anymore](https://issuetracker.google.com/issues/173337263) on Pixel devices with (upgraded to?) Android 11
 
 ## Planned features
 
@@ -861,7 +862,7 @@ The error *... Connection refused ...* means that the email server or something
 
 The error *... Network unreachable ...* means that the email server was not reachable via the current internet connection, for example because internet traffic is restricted to local traffic only.
 
-The error *... Host is unresolved ...* or "*... Unable to resolve host ...* means that the address of the email server could not be resolved. This might be caused by ad blocking or an unreachable or not properly working [DNS](https://en.wikipedia.org/wiki/Domain_Name_System) server.
+The error *... Host is unresolved ...*, *... Unable to resolve host ...* or *... No address associated with hostname ...* means that the address of the email server could not be resolved into an IP address. This might be caused by a VPN, ad blocking or an unreachable or not properly working (local) [DNS](https://en.wikipedia.org/wiki/Domain_Name_System) server.
 
 The error *... Software caused connection abort ...* means that the email server or something between FairEmail and the email server actively terminated an existing connection. This can for example happen when connectivity was abruptly lost. A typical example is turning on flight mode.
 
@@ -2162,14 +2163,12 @@ Disabling *Partial fetch* will result in more memory usage.
 <a name="faq111"></a>
 **(111) Is OAuth supported?**
 
-OAuth for Gmail is supported via the quick setup wizard. The Android account manager will be used to fetch and refresh OAuth tokens for selected on-device accounts. OAuth for non on-device accounts is not supported because Google requires a [yearly security audit](https://support.google.com/cloud/answer/9110914) ($15,000 to $75,000) for this.
+OAuth for Gmail is supported via the quick setup wizard. The Android account manager will be used to fetch and refresh OAuth tokens for selected on-device accounts. OAuth for non on-device accounts is not supported because Google requires a [yearly security audit](https://support.google.com/cloud/answer/9110914) ($15,000 to $75,000) for this. You can read more about this [here](https://www.theregister.com/2019/02/11/google_gmail_developer/).
 
-OAuth for Yandex is supported via the quick setup wizard.
+OAuth for Yandex and Yahoo is supported via the quick setup wizard.
 
 OAuth for Office 365 accounts is supported, but Microsoft does not offer OAuth for Outlook, Live and Hotmail accounts (yet?).
 
-OAuth access for Yahoo was requested, but Yahoo never responded to the request. OAuth for AOL [was deactivated](https://www.programmableweb.com/api/aol-open-auth) by AOL. Verizon owns both AOL and Yahoo, collectively named [Oath inc](https://en.wikipedia.org/wiki/Verizon_Media). So, it is reasonable to assume that OAuth is not supported by Yahoo anymore too.
-
 <br />
 
 <a name="faq112"></a>
@@ -2302,8 +2301,6 @@ FairEmail groups messages based on the standard *Message-ID*, *In-Reply-To* and
 
 When FairEmail cannot connect to an email server to receive messages, for example when the internet connection is bad or a firewall or a VPN is blocking the connection, FairEmail will wait 8, 16 and 32 seconds while keeping the device awake (=use battery power) and try again to connect. If this fails, FairEmail will schedule an alarm to retry after 15, 30 and 60 minutes and let the device sleep (=no battery usage).
 
-Between connectivity changes there is a wait of 90 seconds to give the email server the opportunity to discover the old connection is broken. This is necessary because the internet connection of a mobile device is often lost abruptly and to prevent the problem described in [this FAQ](#user-content-faq23).
-
 Note that [Android doze mode](https://developer.android.com/training/monitoring-device-state/doze-standby) does not allow to wake the device earlier than after 15 minutes.
 
 *Force sync* in the three-dots menu of the unified inbox can be used to let FairEmail attempt to reconnect without waiting.
@@ -2777,6 +2774,8 @@ Updating once a week will probably be sufficient, please see [here](https://gith
 
 Permanent deletion means that messages will *irreversibly* be lost, and to prevent this from happening accidentally, this always needs to be confirmed. Even with a confirmation, some very angry people who lost some of their messages through their own fault contacted me, which was a rather unpleasant experience :-(
 
+Advanced: the IMAP delete flag in combination with the EXPUNGE command is not supportable because both email servers and not all people can handle this, risking unexpected loss of messages. A complicating factor is that not all email servers support [UID EXPUNGE](https://tools.ietf.org/html/rfc4315).
+
 <br />
 
 <a name="faq161"></a>
diff --git a/docs/FAQ-ko-rKR.md b/docs/FAQ-ko-rKR.md
index f920983115..cc58d3d8d1 100644
--- a/docs/FAQ-ko-rKR.md
+++ b/docs/FAQ-ko-rKR.md
@@ -78,6 +78,7 @@ Searching for *IMAP* and the name of the provider is mostly sufficient to find t
 * A preview of a message text doesn't (always) appear on Samsung watches because [setLocalOnly](https://developer.android.com/reference/androidx/core/app/NotificationCompat.Builder.html#setLocalOnly(boolean)) seem to be ignored. Message preview texts are known to be displayed correctly on Pebble 2, Fitbit Charge 3, Mi band 3, and Xiaomi Amazfit BIP wearables. See also [this FAQ](#user-content-faq126).
 * A [bug in Android 6.0](https://issuetracker.google.com/issues/37068143) causes a crash with *... Invalid offset: ... Valid range is ...* when text is selected and tapping outside of the selected text. This bug has been fixed in Android 6.0.1.
 * Internal (anchor) links will not work because original messages are shown in an embedded WebView in a scrolling view (the conversation list). This is an Android limitation which cannot be fixed or worked around.
+* Language detection [is not working anymore](https://issuetracker.google.com/issues/173337263) on Pixel devices with (upgraded to?) Android 11
 
 ## Planned features
 
@@ -861,7 +862,7 @@ The error *... Connection refused ...* means that the email server or something
 
 The error *... Network unreachable ...* means that the email server was not reachable via the current internet connection, for example because internet traffic is restricted to local traffic only.
 
-The error *... Host is unresolved ...* or "*... Unable to resolve host ...* means that the address of the email server could not be resolved. This might be caused by ad blocking or an unreachable or not properly working [DNS](https://en.wikipedia.org/wiki/Domain_Name_System) server.
+The error *... Host is unresolved ...*, *... Unable to resolve host ...* or *... No address associated with hostname ...* means that the address of the email server could not be resolved into an IP address. This might be caused by a VPN, ad blocking or an unreachable or not properly working (local) [DNS](https://en.wikipedia.org/wiki/Domain_Name_System) server.
 
 The error *... Software caused connection abort ...* means that the email server or something between FairEmail and the email server actively terminated an existing connection. This can for example happen when connectivity was abruptly lost. A typical example is turning on flight mode.
 
@@ -2162,14 +2163,12 @@ Disabling *Partial fetch* will result in more memory usage.
 <a name="faq111"></a>
 **(111) Is OAuth supported?**
 
-OAuth for Gmail is supported via the quick setup wizard. The Android account manager will be used to fetch and refresh OAuth tokens for selected on-device accounts. OAuth for non on-device accounts is not supported because Google requires a [yearly security audit](https://support.google.com/cloud/answer/9110914) ($15,000 to $75,000) for this.
+OAuth for Gmail is supported via the quick setup wizard. The Android account manager will be used to fetch and refresh OAuth tokens for selected on-device accounts. OAuth for non on-device accounts is not supported because Google requires a [yearly security audit](https://support.google.com/cloud/answer/9110914) ($15,000 to $75,000) for this. You can read more about this [here](https://www.theregister.com/2019/02/11/google_gmail_developer/).
 
-OAuth for Yandex is supported via the quick setup wizard.
+OAuth for Yandex and Yahoo is supported via the quick setup wizard.
 
 OAuth for Office 365 accounts is supported, but Microsoft does not offer OAuth for Outlook, Live and Hotmail accounts (yet?).
 
-OAuth access for Yahoo was requested, but Yahoo never responded to the request. OAuth for AOL [was deactivated](https://www.programmableweb.com/api/aol-open-auth) by AOL. Verizon owns both AOL and Yahoo, collectively named [Oath inc](https://en.wikipedia.org/wiki/Verizon_Media). So, it is reasonable to assume that OAuth is not supported by Yahoo anymore too.
-
 <br />
 
 <a name="faq112"></a>
@@ -2302,8 +2301,6 @@ FairEmail groups messages based on the standard *Message-ID*, *In-Reply-To* and
 
 When FairEmail cannot connect to an email server to receive messages, for example when the internet connection is bad or a firewall or a VPN is blocking the connection, FairEmail will wait 8, 16 and 32 seconds while keeping the device awake (=use battery power) and try again to connect. If this fails, FairEmail will schedule an alarm to retry after 15, 30 and 60 minutes and let the device sleep (=no battery usage).
 
-Between connectivity changes there is a wait of 90 seconds to give the email server the opportunity to discover the old connection is broken. This is necessary because the internet connection of a mobile device is often lost abruptly and to prevent the problem described in [this FAQ](#user-content-faq23).
-
 Note that [Android doze mode](https://developer.android.com/training/monitoring-device-state/doze-standby) does not allow to wake the device earlier than after 15 minutes.
 
 *Force sync* in the three-dots menu of the unified inbox can be used to let FairEmail attempt to reconnect without waiting.
@@ -2777,6 +2774,8 @@ Updating once a week will probably be sufficient, please see [here](https://gith
 
 Permanent deletion means that messages will *irreversibly* be lost, and to prevent this from happening accidentally, this always needs to be confirmed. Even with a confirmation, some very angry people who lost some of their messages through their own fault contacted me, which was a rather unpleasant experience :-(
 
+Advanced: the IMAP delete flag in combination with the EXPUNGE command is not supportable because both email servers and not all people can handle this, risking unexpected loss of messages. A complicating factor is that not all email servers support [UID EXPUNGE](https://tools.ietf.org/html/rfc4315).
+
 <br />
 
 <a name="faq161"></a>
diff --git a/docs/FAQ-lt-rLT.md b/docs/FAQ-lt-rLT.md
index 7b7b451250..a593607a58 100644
--- a/docs/FAQ-lt-rLT.md
+++ b/docs/FAQ-lt-rLT.md
@@ -78,6 +78,7 @@ Related questions:
 * A preview of a message text doesn't (always) appear on Samsung watches because [setLocalOnly](https://developer.android.com/reference/androidx/core/app/NotificationCompat.Builder.html#setLocalOnly(boolean)) seem to be ignored. Message preview texts are known to be displayed correctly on Pebble 2, Fitbit Charge 3, Mi band 3, and Xiaomi Amazfit BIP wearables. See also [this FAQ](#user-content-faq126).
 * A [bug in Android 6.0](https://issuetracker.google.com/issues/37068143) causes a crash with *... Invalid offset: ... Valid range is ...* when text is selected and tapping outside of the selected text. This bug has been fixed in Android 6.0.1.
 * Internal (anchor) links will not work because original messages are shown in an embedded WebView in a scrolling view (the conversation list). This is an Android limitation which cannot be fixed or worked around.
+* Language detection [is not working anymore](https://issuetracker.google.com/issues/173337263) on Pixel devices with (upgraded to?) Android 11
 
 ## Planned features
 
@@ -861,7 +862,7 @@ The error *... Connection refused ...* means that the email server or something
 
 The error *... Network unreachable ...* means that the email server was not reachable via the current internet connection, for example because internet traffic is restricted to local traffic only.
 
-The error *... Host is unresolved ...* or "*... Unable to resolve host ...* means that the address of the email server could not be resolved. This might be caused by ad blocking or an unreachable or not properly working [DNS](https://en.wikipedia.org/wiki/Domain_Name_System) server.
+The error *... Host is unresolved ...*, *... Unable to resolve host ...* or *... No address associated with hostname ...* means that the address of the email server could not be resolved into an IP address. This might be caused by a VPN, ad blocking or an unreachable or not properly working (local) [DNS](https://en.wikipedia.org/wiki/Domain_Name_System) server.
 
 The error *... Software caused connection abort ...* means that the email server or something between FairEmail and the email server actively terminated an existing connection. This can for example happen when connectivity was abruptly lost. A typical example is turning on flight mode.
 
@@ -2162,14 +2163,12 @@ Disabling *Partial fetch* will result in more memory usage.
 <a name="faq111"></a>
 **(111) Is OAuth supported?**
 
-OAuth for Gmail is supported via the quick setup wizard. The Android account manager will be used to fetch and refresh OAuth tokens for selected on-device accounts. OAuth for non on-device accounts is not supported because Google requires a [yearly security audit](https://support.google.com/cloud/answer/9110914) ($15,000 to $75,000) for this.
+OAuth for Gmail is supported via the quick setup wizard. The Android account manager will be used to fetch and refresh OAuth tokens for selected on-device accounts. OAuth for non on-device accounts is not supported because Google requires a [yearly security audit](https://support.google.com/cloud/answer/9110914) ($15,000 to $75,000) for this. You can read more about this [here](https://www.theregister.com/2019/02/11/google_gmail_developer/).
 
-OAuth for Yandex is supported via the quick setup wizard.
+OAuth for Yandex and Yahoo is supported via the quick setup wizard.
 
 OAuth for Office 365 accounts is supported, but Microsoft does not offer OAuth for Outlook, Live and Hotmail accounts (yet?).
 
-OAuth access for Yahoo was requested, but Yahoo never responded to the request. OAuth for AOL [was deactivated](https://www.programmableweb.com/api/aol-open-auth) by AOL. Verizon owns both AOL and Yahoo, collectively named [Oath inc](https://en.wikipedia.org/wiki/Verizon_Media). So, it is reasonable to assume that OAuth is not supported by Yahoo anymore too.
-
 <br />
 
 <a name="faq112"></a>
@@ -2302,8 +2301,6 @@ FairEmail groups messages based on the standard *Message-ID*, *In-Reply-To* and
 
 When FairEmail cannot connect to an email server to receive messages, for example when the internet connection is bad or a firewall or a VPN is blocking the connection, FairEmail will wait 8, 16 and 32 seconds while keeping the device awake (=use battery power) and try again to connect. If this fails, FairEmail will schedule an alarm to retry after 15, 30 and 60 minutes and let the device sleep (=no battery usage).
 
-Between connectivity changes there is a wait of 90 seconds to give the email server the opportunity to discover the old connection is broken. This is necessary because the internet connection of a mobile device is often lost abruptly and to prevent the problem described in [this FAQ](#user-content-faq23).
-
 Note that [Android doze mode](https://developer.android.com/training/monitoring-device-state/doze-standby) does not allow to wake the device earlier than after 15 minutes.
 
 *Force sync* in the three-dots menu of the unified inbox can be used to let FairEmail attempt to reconnect without waiting.
@@ -2777,6 +2774,8 @@ Updating once a week will probably be sufficient, please see [here](https://gith
 
 Permanent deletion means that messages will *irreversibly* be lost, and to prevent this from happening accidentally, this always needs to be confirmed. Even with a confirmation, some very angry people who lost some of their messages through their own fault contacted me, which was a rather unpleasant experience :-(
 
+Advanced: the IMAP delete flag in combination with the EXPUNGE command is not supportable because both email servers and not all people can handle this, risking unexpected loss of messages. A complicating factor is that not all email servers support [UID EXPUNGE](https://tools.ietf.org/html/rfc4315).
+
 <br />
 
 <a name="faq161"></a>
diff --git a/docs/FAQ-nl-rNL.md b/docs/FAQ-nl-rNL.md
index f598963a61..7d37f85fc1 100644
--- a/docs/FAQ-nl-rNL.md
+++ b/docs/FAQ-nl-rNL.md
@@ -78,6 +78,7 @@ Gerelateerde vragen:
 * A preview of a message text doesn't (always) appear on Samsung watches because [setLocalOnly](https://developer.android.com/reference/androidx/core/app/NotificationCompat.Builder.html#setLocalOnly(boolean)) seem to be ignored. Message preview texts are known to be displayed correctly on Pebble 2, Fitbit Charge 3, Mi band 3, and Xiaomi Amazfit BIP wearables. See also [this FAQ](#user-content-faq126).
 * A [bug in Android 6.0](https://issuetracker.google.com/issues/37068143) causes a crash with *... Invalid offset: ... Valid range is ...* when text is selected and tapping outside of the selected text. This bug has been fixed in Android 6.0.1.
 * Internal (anchor) links will not work because original messages are shown in an embedded WebView in a scrolling view (the conversation list). This is an Android limitation which cannot be fixed or worked around.
+* Language detection [is not working anymore](https://issuetracker.google.com/issues/173337263) on Pixel devices with (upgraded to?) Android 11
 
 ## Geplande functies
 
@@ -861,7 +862,7 @@ The error *... Connection refused ...* means that the email server or something
 
 The error *... Network unreachable ...* means that the email server was not reachable via the current internet connection, for example because internet traffic is restricted to local traffic only.
 
-The error *... Host is unresolved ...* or "*... Unable to resolve host ...* means that the address of the email server could not be resolved. This might be caused by ad blocking or an unreachable or not properly working [DNS](https://en.wikipedia.org/wiki/Domain_Name_System) server.
+The error *... Host is unresolved ...*, *... Unable to resolve host ...* or *... No address associated with hostname ...* means that the address of the email server could not be resolved into an IP address. This might be caused by a VPN, ad blocking or an unreachable or not properly working (local) [DNS](https://en.wikipedia.org/wiki/Domain_Name_System) server.
 
 The error *... Software caused connection abort ...* means that the email server or something between FairEmail and the email server actively terminated an existing connection. This can for example happen when connectivity was abruptly lost. A typical example is turning on flight mode.
 
@@ -2162,14 +2163,12 @@ Disabling *Partial fetch* will result in more memory usage.
 <a name="faq111"></a>
 **(111) Is OAuth supported?**
 
-OAuth for Gmail is supported via the quick setup wizard. The Android account manager will be used to fetch and refresh OAuth tokens for selected on-device accounts. OAuth for non on-device accounts is not supported because Google requires a [yearly security audit](https://support.google.com/cloud/answer/9110914) ($15,000 to $75,000) for this.
+OAuth for Gmail is supported via the quick setup wizard. The Android account manager will be used to fetch and refresh OAuth tokens for selected on-device accounts. OAuth for non on-device accounts is not supported because Google requires a [yearly security audit](https://support.google.com/cloud/answer/9110914) ($15,000 to $75,000) for this. You can read more about this [here](https://www.theregister.com/2019/02/11/google_gmail_developer/).
 
-OAuth for Yandex is supported via the quick setup wizard.
+OAuth for Yandex and Yahoo is supported via the quick setup wizard.
 
 OAuth for Office 365 accounts is supported, but Microsoft does not offer OAuth for Outlook, Live and Hotmail accounts (yet?).
 
-OAuth access for Yahoo was requested, but Yahoo never responded to the request. OAuth for AOL [was deactivated](https://www.programmableweb.com/api/aol-open-auth) by AOL. Verizon owns both AOL and Yahoo, collectively named [Oath inc](https://en.wikipedia.org/wiki/Verizon_Media). So, it is reasonable to assume that OAuth is not supported by Yahoo anymore too.
-
 <br />
 
 <a name="faq112"></a>
@@ -2302,8 +2301,6 @@ FairEmail groups messages based on the standard *Message-ID*, *In-Reply-To* and
 
 When FairEmail cannot connect to an email server to receive messages, for example when the internet connection is bad or a firewall or a VPN is blocking the connection, FairEmail will wait 8, 16 and 32 seconds while keeping the device awake (=use battery power) and try again to connect. If this fails, FairEmail will schedule an alarm to retry after 15, 30 and 60 minutes and let the device sleep (=no battery usage).
 
-Between connectivity changes there is a wait of 90 seconds to give the email server the opportunity to discover the old connection is broken. This is necessary because the internet connection of a mobile device is often lost abruptly and to prevent the problem described in [this FAQ](#user-content-faq23).
-
 Note that [Android doze mode](https://developer.android.com/training/monitoring-device-state/doze-standby) does not allow to wake the device earlier than after 15 minutes.
 
 *Force sync* in the three-dots menu of the unified inbox can be used to let FairEmail attempt to reconnect without waiting.
@@ -2777,6 +2774,8 @@ Updating once a week will probably be sufficient, please see [here](https://gith
 
 Permanent deletion means that messages will *irreversibly* be lost, and to prevent this from happening accidentally, this always needs to be confirmed. Even with a confirmation, some very angry people who lost some of their messages through their own fault contacted me, which was a rather unpleasant experience :-(
 
+Advanced: the IMAP delete flag in combination with the EXPUNGE command is not supportable because both email servers and not all people can handle this, risking unexpected loss of messages. A complicating factor is that not all email servers support [UID EXPUNGE](https://tools.ietf.org/html/rfc4315).
+
 <br />
 
 <a name="faq161"></a>
diff --git a/docs/FAQ-nn-rNO.md b/docs/FAQ-nn-rNO.md
index c20d1c0469..034090c129 100644
--- a/docs/FAQ-nn-rNO.md
+++ b/docs/FAQ-nn-rNO.md
@@ -78,6 +78,7 @@ Relaterte spørsmål:
 * En forhåndsvisning av en meldingstekst vises ikke (alltid) på Samsung-klokker fordi [setLocalOnly](https://developer.android.com/reference/androidx/core/app/NotificationCompat.Builder.html#setLocalOnly(boolean)) ser ut til å bli ignorert. Message preview texts are known to be displayed correctly on Pebble 2, Fitbit Charge 3, Mi band 3, and Xiaomi Amazfit BIP wearables. Se også [denne vanlige FAQ](#user-content-faq126).
 * A [bug in Android 6.0](https://issuetracker.google.com/issues/37068143) causes a crash with *... Invalid offset: ... Valid range is ...* when text is selected and tapping outside of the selected text. This bug has been fixed in Android 6.0.1.
 * Internal (anchor) links will not work because original messages are shown in an embedded WebView in a scrolling view (the conversation list). This is an Android limitation which cannot be fixed or worked around.
+* Language detection [is not working anymore](https://issuetracker.google.com/issues/173337263) on Pixel devices with (upgraded to?) Android 11
 
 ## Planlagte funksjoner
 
@@ -861,7 +862,7 @@ The error *... Connection refused ...* means that the email server or something
 
 The error *... Network unreachable ...* means that the email server was not reachable via the current internet connection, for example because internet traffic is restricted to local traffic only.
 
-The error *... Host is unresolved ...* or "*... Unable to resolve host ...* means that the address of the email server could not be resolved. This might be caused by ad blocking or an unreachable or not properly working [DNS](https://en.wikipedia.org/wiki/Domain_Name_System) server.
+The error *... Host is unresolved ...*, *... Unable to resolve host ...* or *... No address associated with hostname ...* means that the address of the email server could not be resolved into an IP address. This might be caused by a VPN, ad blocking or an unreachable or not properly working (local) [DNS](https://en.wikipedia.org/wiki/Domain_Name_System) server.
 
 The error *... Software caused connection abort ...* means that the email server or something between FairEmail and the email server actively terminated an existing connection. This can for example happen when connectivity was abruptly lost. A typical example is turning on flight mode.
 
@@ -2162,14 +2163,12 @@ Disabling *Partial fetch* will result in more memory usage.
 <a name="faq111"></a>
 **(111) Is OAuth supported?**
 
-OAuth for Gmail is supported via the quick setup wizard. The Android account manager will be used to fetch and refresh OAuth tokens for selected on-device accounts. OAuth for non on-device accounts is not supported because Google requires a [yearly security audit](https://support.google.com/cloud/answer/9110914) ($15,000 to $75,000) for this.
+OAuth for Gmail is supported via the quick setup wizard. The Android account manager will be used to fetch and refresh OAuth tokens for selected on-device accounts. OAuth for non on-device accounts is not supported because Google requires a [yearly security audit](https://support.google.com/cloud/answer/9110914) ($15,000 to $75,000) for this. You can read more about this [here](https://www.theregister.com/2019/02/11/google_gmail_developer/).
 
-OAuth for Yandex is supported via the quick setup wizard.
+OAuth for Yandex and Yahoo is supported via the quick setup wizard.
 
 OAuth for Office 365 accounts is supported, but Microsoft does not offer OAuth for Outlook, Live and Hotmail accounts (yet?).
 
-OAuth access for Yahoo was requested, but Yahoo never responded to the request. OAuth for AOL [was deactivated](https://www.programmableweb.com/api/aol-open-auth) by AOL. Verizon owns both AOL and Yahoo, collectively named [Oath inc](https://en.wikipedia.org/wiki/Verizon_Media). So, it is reasonable to assume that OAuth is not supported by Yahoo anymore too.
-
 <br />
 
 <a name="faq112"></a>
@@ -2302,8 +2301,6 @@ FairEmail groups messages based on the standard *Message-ID*, *In-Reply-To* and
 
 When FairEmail cannot connect to an email server to receive messages, for example when the internet connection is bad or a firewall or a VPN is blocking the connection, FairEmail will wait 8, 16 and 32 seconds while keeping the device awake (=use battery power) and try again to connect. If this fails, FairEmail will schedule an alarm to retry after 15, 30 and 60 minutes and let the device sleep (=no battery usage).
 
-Between connectivity changes there is a wait of 90 seconds to give the email server the opportunity to discover the old connection is broken. This is necessary because the internet connection of a mobile device is often lost abruptly and to prevent the problem described in [this FAQ](#user-content-faq23).
-
 Note that [Android doze mode](https://developer.android.com/training/monitoring-device-state/doze-standby) does not allow to wake the device earlier than after 15 minutes.
 
 *Force sync* in the three-dots menu of the unified inbox can be used to let FairEmail attempt to reconnect without waiting.
@@ -2777,6 +2774,8 @@ Updating once a week will probably be sufficient, please see [here](https://gith
 
 Permanent deletion means that messages will *irreversibly* be lost, and to prevent this from happening accidentally, this always needs to be confirmed. Even with a confirmation, some very angry people who lost some of their messages through their own fault contacted me, which was a rather unpleasant experience :-(
 
+Advanced: the IMAP delete flag in combination with the EXPUNGE command is not supportable because both email servers and not all people can handle this, risking unexpected loss of messages. A complicating factor is that not all email servers support [UID EXPUNGE](https://tools.ietf.org/html/rfc4315).
+
 <br />
 
 <a name="faq161"></a>
diff --git a/docs/FAQ-no-rNO.md b/docs/FAQ-no-rNO.md
index c20d1c0469..034090c129 100644
--- a/docs/FAQ-no-rNO.md
+++ b/docs/FAQ-no-rNO.md
@@ -78,6 +78,7 @@ Relaterte spørsmål:
 * En forhåndsvisning av en meldingstekst vises ikke (alltid) på Samsung-klokker fordi [setLocalOnly](https://developer.android.com/reference/androidx/core/app/NotificationCompat.Builder.html#setLocalOnly(boolean)) ser ut til å bli ignorert. Message preview texts are known to be displayed correctly on Pebble 2, Fitbit Charge 3, Mi band 3, and Xiaomi Amazfit BIP wearables. Se også [denne vanlige FAQ](#user-content-faq126).
 * A [bug in Android 6.0](https://issuetracker.google.com/issues/37068143) causes a crash with *... Invalid offset: ... Valid range is ...* when text is selected and tapping outside of the selected text. This bug has been fixed in Android 6.0.1.
 * Internal (anchor) links will not work because original messages are shown in an embedded WebView in a scrolling view (the conversation list). This is an Android limitation which cannot be fixed or worked around.
+* Language detection [is not working anymore](https://issuetracker.google.com/issues/173337263) on Pixel devices with (upgraded to?) Android 11
 
 ## Planlagte funksjoner
 
@@ -861,7 +862,7 @@ The error *... Connection refused ...* means that the email server or something
 
 The error *... Network unreachable ...* means that the email server was not reachable via the current internet connection, for example because internet traffic is restricted to local traffic only.
 
-The error *... Host is unresolved ...* or "*... Unable to resolve host ...* means that the address of the email server could not be resolved. This might be caused by ad blocking or an unreachable or not properly working [DNS](https://en.wikipedia.org/wiki/Domain_Name_System) server.
+The error *... Host is unresolved ...*, *... Unable to resolve host ...* or *... No address associated with hostname ...* means that the address of the email server could not be resolved into an IP address. This might be caused by a VPN, ad blocking or an unreachable or not properly working (local) [DNS](https://en.wikipedia.org/wiki/Domain_Name_System) server.
 
 The error *... Software caused connection abort ...* means that the email server or something between FairEmail and the email server actively terminated an existing connection. This can for example happen when connectivity was abruptly lost. A typical example is turning on flight mode.
 
@@ -2162,14 +2163,12 @@ Disabling *Partial fetch* will result in more memory usage.
 <a name="faq111"></a>
 **(111) Is OAuth supported?**
 
-OAuth for Gmail is supported via the quick setup wizard. The Android account manager will be used to fetch and refresh OAuth tokens for selected on-device accounts. OAuth for non on-device accounts is not supported because Google requires a [yearly security audit](https://support.google.com/cloud/answer/9110914) ($15,000 to $75,000) for this.
+OAuth for Gmail is supported via the quick setup wizard. The Android account manager will be used to fetch and refresh OAuth tokens for selected on-device accounts. OAuth for non on-device accounts is not supported because Google requires a [yearly security audit](https://support.google.com/cloud/answer/9110914) ($15,000 to $75,000) for this. You can read more about this [here](https://www.theregister.com/2019/02/11/google_gmail_developer/).
 
-OAuth for Yandex is supported via the quick setup wizard.
+OAuth for Yandex and Yahoo is supported via the quick setup wizard.
 
 OAuth for Office 365 accounts is supported, but Microsoft does not offer OAuth for Outlook, Live and Hotmail accounts (yet?).
 
-OAuth access for Yahoo was requested, but Yahoo never responded to the request. OAuth for AOL [was deactivated](https://www.programmableweb.com/api/aol-open-auth) by AOL. Verizon owns both AOL and Yahoo, collectively named [Oath inc](https://en.wikipedia.org/wiki/Verizon_Media). So, it is reasonable to assume that OAuth is not supported by Yahoo anymore too.
-
 <br />
 
 <a name="faq112"></a>
@@ -2302,8 +2301,6 @@ FairEmail groups messages based on the standard *Message-ID*, *In-Reply-To* and
 
 When FairEmail cannot connect to an email server to receive messages, for example when the internet connection is bad or a firewall or a VPN is blocking the connection, FairEmail will wait 8, 16 and 32 seconds while keeping the device awake (=use battery power) and try again to connect. If this fails, FairEmail will schedule an alarm to retry after 15, 30 and 60 minutes and let the device sleep (=no battery usage).
 
-Between connectivity changes there is a wait of 90 seconds to give the email server the opportunity to discover the old connection is broken. This is necessary because the internet connection of a mobile device is often lost abruptly and to prevent the problem described in [this FAQ](#user-content-faq23).
-
 Note that [Android doze mode](https://developer.android.com/training/monitoring-device-state/doze-standby) does not allow to wake the device earlier than after 15 minutes.
 
 *Force sync* in the three-dots menu of the unified inbox can be used to let FairEmail attempt to reconnect without waiting.
@@ -2777,6 +2774,8 @@ Updating once a week will probably be sufficient, please see [here](https://gith
 
 Permanent deletion means that messages will *irreversibly* be lost, and to prevent this from happening accidentally, this always needs to be confirmed. Even with a confirmation, some very angry people who lost some of their messages through their own fault contacted me, which was a rather unpleasant experience :-(
 
+Advanced: the IMAP delete flag in combination with the EXPUNGE command is not supportable because both email servers and not all people can handle this, risking unexpected loss of messages. A complicating factor is that not all email servers support [UID EXPUNGE](https://tools.ietf.org/html/rfc4315).
+
 <br />
 
 <a name="faq161"></a>
diff --git a/docs/FAQ-pl-rPL.md b/docs/FAQ-pl-rPL.md
index 5553b811b0..4dfa2df193 100644
--- a/docs/FAQ-pl-rPL.md
+++ b/docs/FAQ-pl-rPL.md
@@ -78,6 +78,7 @@ Powiązane pytania:
 * Podgląd tekstu wiadomości nie (zawsze) pojawia się na zegarku Samsung, ponieważ [setLocalOnly](https://developer.android.com/reference/androidx/core/app/NotificationCompat.Builder.html#setLocalOnly(boolean)) wydaje się być ignorowany. Wiadomo, że podglądy wiadomości są wyświetlane poprawnie na Pebble 2, Fitbit Charge 3, Mi band 3 i Xiaomi Amazfit BIP. Zobacz również [ten FAQ](#user-content-faq126).
 * [błąd w Android 6.0](https://issuetracker.google.com/issues/37068143) powoduje awarię z *... Invalid offset: ... Valid range is ...* when text is selected and tapping outside of the selected text. Ten błąd został naprawiony w Androidzie 6.0.1.
 * Internal (anchor) links will not work because original messages are shown in an embedded WebView in a scrolling view (the conversation list). Jest to ograniczenie Androida, które nie może być naprawione.
+* Language detection [is not working anymore](https://issuetracker.google.com/issues/173337263) on Pixel devices with (upgraded to?) Android 11
 
 ## Planowane funkcje
 
@@ -861,7 +862,7 @@ The error *... Connection refused ...* means that the email server or something
 
 The error *... Network unreachable ...* means that the email server was not reachable via the current internet connection, for example because internet traffic is restricted to local traffic only.
 
-The error *... Host is unresolved ...* or "*... Unable to resolve host ...* means that the address of the email server could not be resolved. This might be caused by ad blocking or an unreachable or not properly working [DNS](https://en.wikipedia.org/wiki/Domain_Name_System) server.
+The error *... Host is unresolved ...*, *... Unable to resolve host ...* or *... No address associated with hostname ...* means that the address of the email server could not be resolved into an IP address. This might be caused by a VPN, ad blocking or an unreachable or not properly working (local) [DNS](https://en.wikipedia.org/wiki/Domain_Name_System) server.
 
 The error *... Software caused connection abort ...* means that the email server or something between FairEmail and the email server actively terminated an existing connection. This can for example happen when connectivity was abruptly lost. A typical example is turning on flight mode.
 
@@ -2162,14 +2163,12 @@ Disabling *Partial fetch* will result in more memory usage.
 <a name="faq111"></a>
 **(111) Is OAuth supported?**
 
-OAuth for Gmail is supported via the quick setup wizard. The Android account manager will be used to fetch and refresh OAuth tokens for selected on-device accounts. OAuth for non on-device accounts is not supported because Google requires a [yearly security audit](https://support.google.com/cloud/answer/9110914) ($15,000 to $75,000) for this.
+OAuth for Gmail is supported via the quick setup wizard. The Android account manager will be used to fetch and refresh OAuth tokens for selected on-device accounts. OAuth for non on-device accounts is not supported because Google requires a [yearly security audit](https://support.google.com/cloud/answer/9110914) ($15,000 to $75,000) for this. You can read more about this [here](https://www.theregister.com/2019/02/11/google_gmail_developer/).
 
-OAuth for Yandex is supported via the quick setup wizard.
+OAuth for Yandex and Yahoo is supported via the quick setup wizard.
 
 OAuth for Office 365 accounts is supported, but Microsoft does not offer OAuth for Outlook, Live and Hotmail accounts (yet?).
 
-OAuth access for Yahoo was requested, but Yahoo never responded to the request. OAuth for AOL [was deactivated](https://www.programmableweb.com/api/aol-open-auth) by AOL. Verizon owns both AOL and Yahoo, collectively named [Oath inc](https://en.wikipedia.org/wiki/Verizon_Media). So, it is reasonable to assume that OAuth is not supported by Yahoo anymore too.
-
 <br />
 
 <a name="faq112"></a>
@@ -2302,8 +2301,6 @@ FairEmail groups messages based on the standard *Message-ID*, *In-Reply-To* and
 
 When FairEmail cannot connect to an email server to receive messages, for example when the internet connection is bad or a firewall or a VPN is blocking the connection, FairEmail will wait 8, 16 and 32 seconds while keeping the device awake (=use battery power) and try again to connect. If this fails, FairEmail will schedule an alarm to retry after 15, 30 and 60 minutes and let the device sleep (=no battery usage).
 
-Between connectivity changes there is a wait of 90 seconds to give the email server the opportunity to discover the old connection is broken. This is necessary because the internet connection of a mobile device is often lost abruptly and to prevent the problem described in [this FAQ](#user-content-faq23).
-
 Note that [Android doze mode](https://developer.android.com/training/monitoring-device-state/doze-standby) does not allow to wake the device earlier than after 15 minutes.
 
 *Force sync* in the three-dots menu of the unified inbox can be used to let FairEmail attempt to reconnect without waiting.
@@ -2777,6 +2774,8 @@ Updating once a week will probably be sufficient, please see [here](https://gith
 
 Permanent deletion means that messages will *irreversibly* be lost, and to prevent this from happening accidentally, this always needs to be confirmed. Even with a confirmation, some very angry people who lost some of their messages through their own fault contacted me, which was a rather unpleasant experience :-(
 
+Advanced: the IMAP delete flag in combination with the EXPUNGE command is not supportable because both email servers and not all people can handle this, risking unexpected loss of messages. A complicating factor is that not all email servers support [UID EXPUNGE](https://tools.ietf.org/html/rfc4315).
+
 <br />
 
 <a name="faq161"></a>
diff --git a/docs/FAQ-pt-rBR.md b/docs/FAQ-pt-rBR.md
index 1b7b879bd8..a981ae7ba6 100644
--- a/docs/FAQ-pt-rBR.md
+++ b/docs/FAQ-pt-rBR.md
@@ -78,6 +78,7 @@ Perguntas relacionadas:
 * A pré-visualização do texto de uma mensagem não aparece (sempre) nos relógios Samsung porque [setLocalOnly](https://developer.android.com/reference/androidx/core/app/NotificationCompat.Builder.html#setLocalOnly(boolean)) parece ser ignorado. Message preview texts are known to be displayed correctly on Pebble 2, Fitbit Charge 3, Mi band 3, and Xiaomi Amazfit BIP wearables. Veja também [ esse FAQ](#user-content-faq126).
 * Um [problema no Android 6.0](https://issuetracker.google.com/issues/37068143) às vezes causa um travamento com a mensagem *... Invalid offset: ... Valid range is ...* ao selecionar o texto e depois tocar fora do texto selecionado. Esse erro foi corrigido no Android 6.0.1.
 * Internal (anchor) links will not work because original messages are shown in an embedded WebView in a scrolling view (the conversation list). This is an Android limitation which cannot be fixed or worked around.
+* Language detection [is not working anymore](https://issuetracker.google.com/issues/173337263) on Pixel devices with (upgraded to?) Android 11
 
 ## Funcionalidades planejadas
 
@@ -861,7 +862,7 @@ The error *... Connection refused ...* means that the email server or something
 
 The error *... Network unreachable ...* means that the email server was not reachable via the current internet connection, for example because internet traffic is restricted to local traffic only.
 
-The error *... Host is unresolved ...* or "*... Unable to resolve host ...* means that the address of the email server could not be resolved. This might be caused by ad blocking or an unreachable or not properly working [DNS](https://en.wikipedia.org/wiki/Domain_Name_System) server.
+The error *... Host is unresolved ...*, *... Unable to resolve host ...* or *... No address associated with hostname ...* means that the address of the email server could not be resolved into an IP address. This might be caused by a VPN, ad blocking or an unreachable or not properly working (local) [DNS](https://en.wikipedia.org/wiki/Domain_Name_System) server.
 
 The error *... Software caused connection abort ...* means that the email server or something between FairEmail and the email server actively terminated an existing connection. This can for example happen when connectivity was abruptly lost. A typical example is turning on flight mode.
 
@@ -2162,14 +2163,12 @@ Disabling *Partial fetch* will result in more memory usage.
 <a name="faq111"></a>
 **(111) Is OAuth supported?**
 
-OAuth for Gmail is supported via the quick setup wizard. The Android account manager will be used to fetch and refresh OAuth tokens for selected on-device accounts. OAuth for non on-device accounts is not supported because Google requires a [yearly security audit](https://support.google.com/cloud/answer/9110914) ($15,000 to $75,000) for this.
+OAuth for Gmail is supported via the quick setup wizard. The Android account manager will be used to fetch and refresh OAuth tokens for selected on-device accounts. OAuth for non on-device accounts is not supported because Google requires a [yearly security audit](https://support.google.com/cloud/answer/9110914) ($15,000 to $75,000) for this. You can read more about this [here](https://www.theregister.com/2019/02/11/google_gmail_developer/).
 
-OAuth for Yandex is supported via the quick setup wizard.
+OAuth for Yandex and Yahoo is supported via the quick setup wizard.
 
 OAuth for Office 365 accounts is supported, but Microsoft does not offer OAuth for Outlook, Live and Hotmail accounts (yet?).
 
-OAuth access for Yahoo was requested, but Yahoo never responded to the request. OAuth for AOL [was deactivated](https://www.programmableweb.com/api/aol-open-auth) by AOL. Verizon owns both AOL and Yahoo, collectively named [Oath inc](https://en.wikipedia.org/wiki/Verizon_Media). So, it is reasonable to assume that OAuth is not supported by Yahoo anymore too.
-
 <br />
 
 <a name="faq112"></a>
@@ -2302,8 +2301,6 @@ FairEmail groups messages based on the standard *Message-ID*, *In-Reply-To* and
 
 When FairEmail cannot connect to an email server to receive messages, for example when the internet connection is bad or a firewall or a VPN is blocking the connection, FairEmail will wait 8, 16 and 32 seconds while keeping the device awake (=use battery power) and try again to connect. If this fails, FairEmail will schedule an alarm to retry after 15, 30 and 60 minutes and let the device sleep (=no battery usage).
 
-Between connectivity changes there is a wait of 90 seconds to give the email server the opportunity to discover the old connection is broken. This is necessary because the internet connection of a mobile device is often lost abruptly and to prevent the problem described in [this FAQ](#user-content-faq23).
-
 Note that [Android doze mode](https://developer.android.com/training/monitoring-device-state/doze-standby) does not allow to wake the device earlier than after 15 minutes.
 
 *Force sync* in the three-dots menu of the unified inbox can be used to let FairEmail attempt to reconnect without waiting.
@@ -2777,6 +2774,8 @@ Updating once a week will probably be sufficient, please see [here](https://gith
 
 Permanent deletion means that messages will *irreversibly* be lost, and to prevent this from happening accidentally, this always needs to be confirmed. Even with a confirmation, some very angry people who lost some of their messages through their own fault contacted me, which was a rather unpleasant experience :-(
 
+Advanced: the IMAP delete flag in combination with the EXPUNGE command is not supportable because both email servers and not all people can handle this, risking unexpected loss of messages. A complicating factor is that not all email servers support [UID EXPUNGE](https://tools.ietf.org/html/rfc4315).
+
 <br />
 
 <a name="faq161"></a>
diff --git a/docs/FAQ-pt-rPT.md b/docs/FAQ-pt-rPT.md
index 7b7b451250..a593607a58 100644
--- a/docs/FAQ-pt-rPT.md
+++ b/docs/FAQ-pt-rPT.md
@@ -78,6 +78,7 @@ Related questions:
 * A preview of a message text doesn't (always) appear on Samsung watches because [setLocalOnly](https://developer.android.com/reference/androidx/core/app/NotificationCompat.Builder.html#setLocalOnly(boolean)) seem to be ignored. Message preview texts are known to be displayed correctly on Pebble 2, Fitbit Charge 3, Mi band 3, and Xiaomi Amazfit BIP wearables. See also [this FAQ](#user-content-faq126).
 * A [bug in Android 6.0](https://issuetracker.google.com/issues/37068143) causes a crash with *... Invalid offset: ... Valid range is ...* when text is selected and tapping outside of the selected text. This bug has been fixed in Android 6.0.1.
 * Internal (anchor) links will not work because original messages are shown in an embedded WebView in a scrolling view (the conversation list). This is an Android limitation which cannot be fixed or worked around.
+* Language detection [is not working anymore](https://issuetracker.google.com/issues/173337263) on Pixel devices with (upgraded to?) Android 11
 
 ## Planned features
 
@@ -861,7 +862,7 @@ The error *... Connection refused ...* means that the email server or something
 
 The error *... Network unreachable ...* means that the email server was not reachable via the current internet connection, for example because internet traffic is restricted to local traffic only.
 
-The error *... Host is unresolved ...* or "*... Unable to resolve host ...* means that the address of the email server could not be resolved. This might be caused by ad blocking or an unreachable or not properly working [DNS](https://en.wikipedia.org/wiki/Domain_Name_System) server.
+The error *... Host is unresolved ...*, *... Unable to resolve host ...* or *... No address associated with hostname ...* means that the address of the email server could not be resolved into an IP address. This might be caused by a VPN, ad blocking or an unreachable or not properly working (local) [DNS](https://en.wikipedia.org/wiki/Domain_Name_System) server.
 
 The error *... Software caused connection abort ...* means that the email server or something between FairEmail and the email server actively terminated an existing connection. This can for example happen when connectivity was abruptly lost. A typical example is turning on flight mode.
 
@@ -2162,14 +2163,12 @@ Disabling *Partial fetch* will result in more memory usage.
 <a name="faq111"></a>
 **(111) Is OAuth supported?**
 
-OAuth for Gmail is supported via the quick setup wizard. The Android account manager will be used to fetch and refresh OAuth tokens for selected on-device accounts. OAuth for non on-device accounts is not supported because Google requires a [yearly security audit](https://support.google.com/cloud/answer/9110914) ($15,000 to $75,000) for this.
+OAuth for Gmail is supported via the quick setup wizard. The Android account manager will be used to fetch and refresh OAuth tokens for selected on-device accounts. OAuth for non on-device accounts is not supported because Google requires a [yearly security audit](https://support.google.com/cloud/answer/9110914) ($15,000 to $75,000) for this. You can read more about this [here](https://www.theregister.com/2019/02/11/google_gmail_developer/).
 
-OAuth for Yandex is supported via the quick setup wizard.
+OAuth for Yandex and Yahoo is supported via the quick setup wizard.
 
 OAuth for Office 365 accounts is supported, but Microsoft does not offer OAuth for Outlook, Live and Hotmail accounts (yet?).
 
-OAuth access for Yahoo was requested, but Yahoo never responded to the request. OAuth for AOL [was deactivated](https://www.programmableweb.com/api/aol-open-auth) by AOL. Verizon owns both AOL and Yahoo, collectively named [Oath inc](https://en.wikipedia.org/wiki/Verizon_Media). So, it is reasonable to assume that OAuth is not supported by Yahoo anymore too.
-
 <br />
 
 <a name="faq112"></a>
@@ -2302,8 +2301,6 @@ FairEmail groups messages based on the standard *Message-ID*, *In-Reply-To* and
 
 When FairEmail cannot connect to an email server to receive messages, for example when the internet connection is bad or a firewall or a VPN is blocking the connection, FairEmail will wait 8, 16 and 32 seconds while keeping the device awake (=use battery power) and try again to connect. If this fails, FairEmail will schedule an alarm to retry after 15, 30 and 60 minutes and let the device sleep (=no battery usage).
 
-Between connectivity changes there is a wait of 90 seconds to give the email server the opportunity to discover the old connection is broken. This is necessary because the internet connection of a mobile device is often lost abruptly and to prevent the problem described in [this FAQ](#user-content-faq23).
-
 Note that [Android doze mode](https://developer.android.com/training/monitoring-device-state/doze-standby) does not allow to wake the device earlier than after 15 minutes.
 
 *Force sync* in the three-dots menu of the unified inbox can be used to let FairEmail attempt to reconnect without waiting.
@@ -2777,6 +2774,8 @@ Updating once a week will probably be sufficient, please see [here](https://gith
 
 Permanent deletion means that messages will *irreversibly* be lost, and to prevent this from happening accidentally, this always needs to be confirmed. Even with a confirmation, some very angry people who lost some of their messages through their own fault contacted me, which was a rather unpleasant experience :-(
 
+Advanced: the IMAP delete flag in combination with the EXPUNGE command is not supportable because both email servers and not all people can handle this, risking unexpected loss of messages. A complicating factor is that not all email servers support [UID EXPUNGE](https://tools.ietf.org/html/rfc4315).
+
 <br />
 
 <a name="faq161"></a>
diff --git a/docs/FAQ-ro-rRO.md b/docs/FAQ-ro-rRO.md
index 7b7b451250..a593607a58 100644
--- a/docs/FAQ-ro-rRO.md
+++ b/docs/FAQ-ro-rRO.md
@@ -78,6 +78,7 @@ Related questions:
 * A preview of a message text doesn't (always) appear on Samsung watches because [setLocalOnly](https://developer.android.com/reference/androidx/core/app/NotificationCompat.Builder.html#setLocalOnly(boolean)) seem to be ignored. Message preview texts are known to be displayed correctly on Pebble 2, Fitbit Charge 3, Mi band 3, and Xiaomi Amazfit BIP wearables. See also [this FAQ](#user-content-faq126).
 * A [bug in Android 6.0](https://issuetracker.google.com/issues/37068143) causes a crash with *... Invalid offset: ... Valid range is ...* when text is selected and tapping outside of the selected text. This bug has been fixed in Android 6.0.1.
 * Internal (anchor) links will not work because original messages are shown in an embedded WebView in a scrolling view (the conversation list). This is an Android limitation which cannot be fixed or worked around.
+* Language detection [is not working anymore](https://issuetracker.google.com/issues/173337263) on Pixel devices with (upgraded to?) Android 11
 
 ## Planned features
 
@@ -861,7 +862,7 @@ The error *... Connection refused ...* means that the email server or something
 
 The error *... Network unreachable ...* means that the email server was not reachable via the current internet connection, for example because internet traffic is restricted to local traffic only.
 
-The error *... Host is unresolved ...* or "*... Unable to resolve host ...* means that the address of the email server could not be resolved. This might be caused by ad blocking or an unreachable or not properly working [DNS](https://en.wikipedia.org/wiki/Domain_Name_System) server.
+The error *... Host is unresolved ...*, *... Unable to resolve host ...* or *... No address associated with hostname ...* means that the address of the email server could not be resolved into an IP address. This might be caused by a VPN, ad blocking or an unreachable or not properly working (local) [DNS](https://en.wikipedia.org/wiki/Domain_Name_System) server.
 
 The error *... Software caused connection abort ...* means that the email server or something between FairEmail and the email server actively terminated an existing connection. This can for example happen when connectivity was abruptly lost. A typical example is turning on flight mode.
 
@@ -2162,14 +2163,12 @@ Disabling *Partial fetch* will result in more memory usage.
 <a name="faq111"></a>
 **(111) Is OAuth supported?**
 
-OAuth for Gmail is supported via the quick setup wizard. The Android account manager will be used to fetch and refresh OAuth tokens for selected on-device accounts. OAuth for non on-device accounts is not supported because Google requires a [yearly security audit](https://support.google.com/cloud/answer/9110914) ($15,000 to $75,000) for this.
+OAuth for Gmail is supported via the quick setup wizard. The Android account manager will be used to fetch and refresh OAuth tokens for selected on-device accounts. OAuth for non on-device accounts is not supported because Google requires a [yearly security audit](https://support.google.com/cloud/answer/9110914) ($15,000 to $75,000) for this. You can read more about this [here](https://www.theregister.com/2019/02/11/google_gmail_developer/).
 
-OAuth for Yandex is supported via the quick setup wizard.
+OAuth for Yandex and Yahoo is supported via the quick setup wizard.
 
 OAuth for Office 365 accounts is supported, but Microsoft does not offer OAuth for Outlook, Live and Hotmail accounts (yet?).
 
-OAuth access for Yahoo was requested, but Yahoo never responded to the request. OAuth for AOL [was deactivated](https://www.programmableweb.com/api/aol-open-auth) by AOL. Verizon owns both AOL and Yahoo, collectively named [Oath inc](https://en.wikipedia.org/wiki/Verizon_Media). So, it is reasonable to assume that OAuth is not supported by Yahoo anymore too.
-
 <br />
 
 <a name="faq112"></a>
@@ -2302,8 +2301,6 @@ FairEmail groups messages based on the standard *Message-ID*, *In-Reply-To* and
 
 When FairEmail cannot connect to an email server to receive messages, for example when the internet connection is bad or a firewall or a VPN is blocking the connection, FairEmail will wait 8, 16 and 32 seconds while keeping the device awake (=use battery power) and try again to connect. If this fails, FairEmail will schedule an alarm to retry after 15, 30 and 60 minutes and let the device sleep (=no battery usage).
 
-Between connectivity changes there is a wait of 90 seconds to give the email server the opportunity to discover the old connection is broken. This is necessary because the internet connection of a mobile device is often lost abruptly and to prevent the problem described in [this FAQ](#user-content-faq23).
-
 Note that [Android doze mode](https://developer.android.com/training/monitoring-device-state/doze-standby) does not allow to wake the device earlier than after 15 minutes.
 
 *Force sync* in the three-dots menu of the unified inbox can be used to let FairEmail attempt to reconnect without waiting.
@@ -2777,6 +2774,8 @@ Updating once a week will probably be sufficient, please see [here](https://gith
 
 Permanent deletion means that messages will *irreversibly* be lost, and to prevent this from happening accidentally, this always needs to be confirmed. Even with a confirmation, some very angry people who lost some of their messages through their own fault contacted me, which was a rather unpleasant experience :-(
 
+Advanced: the IMAP delete flag in combination with the EXPUNGE command is not supportable because both email servers and not all people can handle this, risking unexpected loss of messages. A complicating factor is that not all email servers support [UID EXPUNGE](https://tools.ietf.org/html/rfc4315).
+
 <br />
 
 <a name="faq161"></a>
diff --git a/docs/FAQ-ru-rRU.md b/docs/FAQ-ru-rRU.md
index f3ed13c046..13c69f94ed 100644
--- a/docs/FAQ-ru-rRU.md
+++ b/docs/FAQ-ru-rRU.md
@@ -78,6 +78,7 @@
 * Предпросмотр текста сообщения (всегда) не отображается на Samsung watch, потому что [setLocalOnly](https://developer.android.com/reference/androidx/core/app/NotificationCompat.Builder.html#setLocalOnly(boolean)), похоже, игнорируется. Message preview texts are known to be displayed correctly on Pebble 2, Fitbit Charge 3, Mi band 3, and Xiaomi Amazfit BIP wearables. См. также [этот FAQ](#user-content-faq126).
 * A [bug in Android 6.0](https://issuetracker.google.com/issues/37068143) causes a crash with *... Недопустимое смещение: ... Valid range is ...* when text is selected and tapping outside of the selected text. This bug has been fixed in Android 6.0.1.
 * Внутренние (якорные) ссылки не будут работать, потому что оригинальные сообщения отображаются во встроенном WebView в виде прокрутки (список разговоров). Это ограничение Android, которое не может быть исправлено или обойдено.
+* Language detection [is not working anymore](https://issuetracker.google.com/issues/173337263) on Pixel devices with (upgraded to?) Android 11
 
 ## Запланированные возможности
 
@@ -861,7 +862,7 @@ The error *... Connection refused ...* means that the email server or something
 
 The error *... Network unreachable ...* means that the email server was not reachable via the current internet connection, for example because internet traffic is restricted to local traffic only.
 
-The error *... Host is unresolved ...* or "*... Unable to resolve host ...* means that the address of the email server could not be resolved. This might be caused by ad blocking or an unreachable or not properly working [DNS](https://en.wikipedia.org/wiki/Domain_Name_System) server.
+The error *... Host is unresolved ...*, *... Unable to resolve host ...* or *... No address associated with hostname ...* means that the address of the email server could not be resolved into an IP address. This might be caused by a VPN, ad blocking or an unreachable or not properly working (local) [DNS](https://en.wikipedia.org/wiki/Domain_Name_System) server.
 
 The error *... Software caused connection abort ...* means that the email server or something between FairEmail and the email server actively terminated an existing connection. This can for example happen when connectivity was abruptly lost. A typical example is turning on flight mode.
 
@@ -2162,14 +2163,12 @@ Disabling *Partial fetch* will result in more memory usage.
 <a name="faq111"></a>
 **(111) Is OAuth supported?**
 
-OAuth for Gmail is supported via the quick setup wizard. The Android account manager will be used to fetch and refresh OAuth tokens for selected on-device accounts. OAuth for non on-device accounts is not supported because Google requires a [yearly security audit](https://support.google.com/cloud/answer/9110914) ($15,000 to $75,000) for this.
+OAuth for Gmail is supported via the quick setup wizard. The Android account manager will be used to fetch and refresh OAuth tokens for selected on-device accounts. OAuth for non on-device accounts is not supported because Google requires a [yearly security audit](https://support.google.com/cloud/answer/9110914) ($15,000 to $75,000) for this. You can read more about this [here](https://www.theregister.com/2019/02/11/google_gmail_developer/).
 
-OAuth for Yandex is supported via the quick setup wizard.
+OAuth for Yandex and Yahoo is supported via the quick setup wizard.
 
 OAuth for Office 365 accounts is supported, but Microsoft does not offer OAuth for Outlook, Live and Hotmail accounts (yet?).
 
-OAuth access for Yahoo was requested, but Yahoo never responded to the request. OAuth for AOL [was deactivated](https://www.programmableweb.com/api/aol-open-auth) by AOL. Verizon owns both AOL and Yahoo, collectively named [Oath inc](https://en.wikipedia.org/wiki/Verizon_Media). So, it is reasonable to assume that OAuth is not supported by Yahoo anymore too.
-
 <br />
 
 <a name="faq112"></a>
@@ -2302,8 +2301,6 @@ FairEmail groups messages based on the standard *Message-ID*, *In-Reply-To* and
 
 When FairEmail cannot connect to an email server to receive messages, for example when the internet connection is bad or a firewall or a VPN is blocking the connection, FairEmail will wait 8, 16 and 32 seconds while keeping the device awake (=use battery power) and try again to connect. If this fails, FairEmail will schedule an alarm to retry after 15, 30 and 60 minutes and let the device sleep (=no battery usage).
 
-Between connectivity changes there is a wait of 90 seconds to give the email server the opportunity to discover the old connection is broken. This is necessary because the internet connection of a mobile device is often lost abruptly and to prevent the problem described in [this FAQ](#user-content-faq23).
-
 Note that [Android doze mode](https://developer.android.com/training/monitoring-device-state/doze-standby) does not allow to wake the device earlier than after 15 minutes.
 
 *Force sync* in the three-dots menu of the unified inbox can be used to let FairEmail attempt to reconnect without waiting.
@@ -2777,6 +2774,8 @@ Updating once a week will probably be sufficient, please see [here](https://gith
 
 Permanent deletion means that messages will *irreversibly* be lost, and to prevent this from happening accidentally, this always needs to be confirmed. Even with a confirmation, some very angry people who lost some of their messages through their own fault contacted me, which was a rather unpleasant experience :-(
 
+Advanced: the IMAP delete flag in combination with the EXPUNGE command is not supportable because both email servers and not all people can handle this, risking unexpected loss of messages. A complicating factor is that not all email servers support [UID EXPUNGE](https://tools.ietf.org/html/rfc4315).
+
 <br />
 
 <a name="faq161"></a>
diff --git a/docs/FAQ-sk-rSK.md b/docs/FAQ-sk-rSK.md
index 7b7b451250..a593607a58 100644
--- a/docs/FAQ-sk-rSK.md
+++ b/docs/FAQ-sk-rSK.md
@@ -78,6 +78,7 @@ Related questions:
 * A preview of a message text doesn't (always) appear on Samsung watches because [setLocalOnly](https://developer.android.com/reference/androidx/core/app/NotificationCompat.Builder.html#setLocalOnly(boolean)) seem to be ignored. Message preview texts are known to be displayed correctly on Pebble 2, Fitbit Charge 3, Mi band 3, and Xiaomi Amazfit BIP wearables. See also [this FAQ](#user-content-faq126).
 * A [bug in Android 6.0](https://issuetracker.google.com/issues/37068143) causes a crash with *... Invalid offset: ... Valid range is ...* when text is selected and tapping outside of the selected text. This bug has been fixed in Android 6.0.1.
 * Internal (anchor) links will not work because original messages are shown in an embedded WebView in a scrolling view (the conversation list). This is an Android limitation which cannot be fixed or worked around.
+* Language detection [is not working anymore](https://issuetracker.google.com/issues/173337263) on Pixel devices with (upgraded to?) Android 11
 
 ## Planned features
 
@@ -861,7 +862,7 @@ The error *... Connection refused ...* means that the email server or something
 
 The error *... Network unreachable ...* means that the email server was not reachable via the current internet connection, for example because internet traffic is restricted to local traffic only.
 
-The error *... Host is unresolved ...* or "*... Unable to resolve host ...* means that the address of the email server could not be resolved. This might be caused by ad blocking or an unreachable or not properly working [DNS](https://en.wikipedia.org/wiki/Domain_Name_System) server.
+The error *... Host is unresolved ...*, *... Unable to resolve host ...* or *... No address associated with hostname ...* means that the address of the email server could not be resolved into an IP address. This might be caused by a VPN, ad blocking or an unreachable or not properly working (local) [DNS](https://en.wikipedia.org/wiki/Domain_Name_System) server.
 
 The error *... Software caused connection abort ...* means that the email server or something between FairEmail and the email server actively terminated an existing connection. This can for example happen when connectivity was abruptly lost. A typical example is turning on flight mode.
 
@@ -2162,14 +2163,12 @@ Disabling *Partial fetch* will result in more memory usage.
 <a name="faq111"></a>
 **(111) Is OAuth supported?**
 
-OAuth for Gmail is supported via the quick setup wizard. The Android account manager will be used to fetch and refresh OAuth tokens for selected on-device accounts. OAuth for non on-device accounts is not supported because Google requires a [yearly security audit](https://support.google.com/cloud/answer/9110914) ($15,000 to $75,000) for this.
+OAuth for Gmail is supported via the quick setup wizard. The Android account manager will be used to fetch and refresh OAuth tokens for selected on-device accounts. OAuth for non on-device accounts is not supported because Google requires a [yearly security audit](https://support.google.com/cloud/answer/9110914) ($15,000 to $75,000) for this. You can read more about this [here](https://www.theregister.com/2019/02/11/google_gmail_developer/).
 
-OAuth for Yandex is supported via the quick setup wizard.
+OAuth for Yandex and Yahoo is supported via the quick setup wizard.
 
 OAuth for Office 365 accounts is supported, but Microsoft does not offer OAuth for Outlook, Live and Hotmail accounts (yet?).
 
-OAuth access for Yahoo was requested, but Yahoo never responded to the request. OAuth for AOL [was deactivated](https://www.programmableweb.com/api/aol-open-auth) by AOL. Verizon owns both AOL and Yahoo, collectively named [Oath inc](https://en.wikipedia.org/wiki/Verizon_Media). So, it is reasonable to assume that OAuth is not supported by Yahoo anymore too.
-
 <br />
 
 <a name="faq112"></a>
@@ -2302,8 +2301,6 @@ FairEmail groups messages based on the standard *Message-ID*, *In-Reply-To* and
 
 When FairEmail cannot connect to an email server to receive messages, for example when the internet connection is bad or a firewall or a VPN is blocking the connection, FairEmail will wait 8, 16 and 32 seconds while keeping the device awake (=use battery power) and try again to connect. If this fails, FairEmail will schedule an alarm to retry after 15, 30 and 60 minutes and let the device sleep (=no battery usage).
 
-Between connectivity changes there is a wait of 90 seconds to give the email server the opportunity to discover the old connection is broken. This is necessary because the internet connection of a mobile device is often lost abruptly and to prevent the problem described in [this FAQ](#user-content-faq23).
-
 Note that [Android doze mode](https://developer.android.com/training/monitoring-device-state/doze-standby) does not allow to wake the device earlier than after 15 minutes.
 
 *Force sync* in the three-dots menu of the unified inbox can be used to let FairEmail attempt to reconnect without waiting.
@@ -2777,6 +2774,8 @@ Updating once a week will probably be sufficient, please see [here](https://gith
 
 Permanent deletion means that messages will *irreversibly* be lost, and to prevent this from happening accidentally, this always needs to be confirmed. Even with a confirmation, some very angry people who lost some of their messages through their own fault contacted me, which was a rather unpleasant experience :-(
 
+Advanced: the IMAP delete flag in combination with the EXPUNGE command is not supportable because both email servers and not all people can handle this, risking unexpected loss of messages. A complicating factor is that not all email servers support [UID EXPUNGE](https://tools.ietf.org/html/rfc4315).
+
 <br />
 
 <a name="faq161"></a>
diff --git a/docs/FAQ-sl-rSI.md b/docs/FAQ-sl-rSI.md
index 7b7b451250..a593607a58 100644
--- a/docs/FAQ-sl-rSI.md
+++ b/docs/FAQ-sl-rSI.md
@@ -78,6 +78,7 @@ Related questions:
 * A preview of a message text doesn't (always) appear on Samsung watches because [setLocalOnly](https://developer.android.com/reference/androidx/core/app/NotificationCompat.Builder.html#setLocalOnly(boolean)) seem to be ignored. Message preview texts are known to be displayed correctly on Pebble 2, Fitbit Charge 3, Mi band 3, and Xiaomi Amazfit BIP wearables. See also [this FAQ](#user-content-faq126).
 * A [bug in Android 6.0](https://issuetracker.google.com/issues/37068143) causes a crash with *... Invalid offset: ... Valid range is ...* when text is selected and tapping outside of the selected text. This bug has been fixed in Android 6.0.1.
 * Internal (anchor) links will not work because original messages are shown in an embedded WebView in a scrolling view (the conversation list). This is an Android limitation which cannot be fixed or worked around.
+* Language detection [is not working anymore](https://issuetracker.google.com/issues/173337263) on Pixel devices with (upgraded to?) Android 11
 
 ## Planned features
 
@@ -861,7 +862,7 @@ The error *... Connection refused ...* means that the email server or something
 
 The error *... Network unreachable ...* means that the email server was not reachable via the current internet connection, for example because internet traffic is restricted to local traffic only.
 
-The error *... Host is unresolved ...* or "*... Unable to resolve host ...* means that the address of the email server could not be resolved. This might be caused by ad blocking or an unreachable or not properly working [DNS](https://en.wikipedia.org/wiki/Domain_Name_System) server.
+The error *... Host is unresolved ...*, *... Unable to resolve host ...* or *... No address associated with hostname ...* means that the address of the email server could not be resolved into an IP address. This might be caused by a VPN, ad blocking or an unreachable or not properly working (local) [DNS](https://en.wikipedia.org/wiki/Domain_Name_System) server.
 
 The error *... Software caused connection abort ...* means that the email server or something between FairEmail and the email server actively terminated an existing connection. This can for example happen when connectivity was abruptly lost. A typical example is turning on flight mode.
 
@@ -2162,14 +2163,12 @@ Disabling *Partial fetch* will result in more memory usage.
 <a name="faq111"></a>
 **(111) Is OAuth supported?**
 
-OAuth for Gmail is supported via the quick setup wizard. The Android account manager will be used to fetch and refresh OAuth tokens for selected on-device accounts. OAuth for non on-device accounts is not supported because Google requires a [yearly security audit](https://support.google.com/cloud/answer/9110914) ($15,000 to $75,000) for this.
+OAuth for Gmail is supported via the quick setup wizard. The Android account manager will be used to fetch and refresh OAuth tokens for selected on-device accounts. OAuth for non on-device accounts is not supported because Google requires a [yearly security audit](https://support.google.com/cloud/answer/9110914) ($15,000 to $75,000) for this. You can read more about this [here](https://www.theregister.com/2019/02/11/google_gmail_developer/).
 
-OAuth for Yandex is supported via the quick setup wizard.
+OAuth for Yandex and Yahoo is supported via the quick setup wizard.
 
 OAuth for Office 365 accounts is supported, but Microsoft does not offer OAuth for Outlook, Live and Hotmail accounts (yet?).
 
-OAuth access for Yahoo was requested, but Yahoo never responded to the request. OAuth for AOL [was deactivated](https://www.programmableweb.com/api/aol-open-auth) by AOL. Verizon owns both AOL and Yahoo, collectively named [Oath inc](https://en.wikipedia.org/wiki/Verizon_Media). So, it is reasonable to assume that OAuth is not supported by Yahoo anymore too.
-
 <br />
 
 <a name="faq112"></a>
@@ -2302,8 +2301,6 @@ FairEmail groups messages based on the standard *Message-ID*, *In-Reply-To* and
 
 When FairEmail cannot connect to an email server to receive messages, for example when the internet connection is bad or a firewall or a VPN is blocking the connection, FairEmail will wait 8, 16 and 32 seconds while keeping the device awake (=use battery power) and try again to connect. If this fails, FairEmail will schedule an alarm to retry after 15, 30 and 60 minutes and let the device sleep (=no battery usage).
 
-Between connectivity changes there is a wait of 90 seconds to give the email server the opportunity to discover the old connection is broken. This is necessary because the internet connection of a mobile device is often lost abruptly and to prevent the problem described in [this FAQ](#user-content-faq23).
-
 Note that [Android doze mode](https://developer.android.com/training/monitoring-device-state/doze-standby) does not allow to wake the device earlier than after 15 minutes.
 
 *Force sync* in the three-dots menu of the unified inbox can be used to let FairEmail attempt to reconnect without waiting.
@@ -2777,6 +2774,8 @@ Updating once a week will probably be sufficient, please see [here](https://gith
 
 Permanent deletion means that messages will *irreversibly* be lost, and to prevent this from happening accidentally, this always needs to be confirmed. Even with a confirmation, some very angry people who lost some of their messages through their own fault contacted me, which was a rather unpleasant experience :-(
 
+Advanced: the IMAP delete flag in combination with the EXPUNGE command is not supportable because both email servers and not all people can handle this, risking unexpected loss of messages. A complicating factor is that not all email servers support [UID EXPUNGE](https://tools.ietf.org/html/rfc4315).
+
 <br />
 
 <a name="faq161"></a>
diff --git a/docs/FAQ-sr-rSP.md b/docs/FAQ-sr-rSP.md
index 7b7b451250..a593607a58 100644
--- a/docs/FAQ-sr-rSP.md
+++ b/docs/FAQ-sr-rSP.md
@@ -78,6 +78,7 @@ Related questions:
 * A preview of a message text doesn't (always) appear on Samsung watches because [setLocalOnly](https://developer.android.com/reference/androidx/core/app/NotificationCompat.Builder.html#setLocalOnly(boolean)) seem to be ignored. Message preview texts are known to be displayed correctly on Pebble 2, Fitbit Charge 3, Mi band 3, and Xiaomi Amazfit BIP wearables. See also [this FAQ](#user-content-faq126).
 * A [bug in Android 6.0](https://issuetracker.google.com/issues/37068143) causes a crash with *... Invalid offset: ... Valid range is ...* when text is selected and tapping outside of the selected text. This bug has been fixed in Android 6.0.1.
 * Internal (anchor) links will not work because original messages are shown in an embedded WebView in a scrolling view (the conversation list). This is an Android limitation which cannot be fixed or worked around.
+* Language detection [is not working anymore](https://issuetracker.google.com/issues/173337263) on Pixel devices with (upgraded to?) Android 11
 
 ## Planned features
 
@@ -861,7 +862,7 @@ The error *... Connection refused ...* means that the email server or something
 
 The error *... Network unreachable ...* means that the email server was not reachable via the current internet connection, for example because internet traffic is restricted to local traffic only.
 
-The error *... Host is unresolved ...* or "*... Unable to resolve host ...* means that the address of the email server could not be resolved. This might be caused by ad blocking or an unreachable or not properly working [DNS](https://en.wikipedia.org/wiki/Domain_Name_System) server.
+The error *... Host is unresolved ...*, *... Unable to resolve host ...* or *... No address associated with hostname ...* means that the address of the email server could not be resolved into an IP address. This might be caused by a VPN, ad blocking or an unreachable or not properly working (local) [DNS](https://en.wikipedia.org/wiki/Domain_Name_System) server.
 
 The error *... Software caused connection abort ...* means that the email server or something between FairEmail and the email server actively terminated an existing connection. This can for example happen when connectivity was abruptly lost. A typical example is turning on flight mode.
 
@@ -2162,14 +2163,12 @@ Disabling *Partial fetch* will result in more memory usage.
 <a name="faq111"></a>
 **(111) Is OAuth supported?**
 
-OAuth for Gmail is supported via the quick setup wizard. The Android account manager will be used to fetch and refresh OAuth tokens for selected on-device accounts. OAuth for non on-device accounts is not supported because Google requires a [yearly security audit](https://support.google.com/cloud/answer/9110914) ($15,000 to $75,000) for this.
+OAuth for Gmail is supported via the quick setup wizard. The Android account manager will be used to fetch and refresh OAuth tokens for selected on-device accounts. OAuth for non on-device accounts is not supported because Google requires a [yearly security audit](https://support.google.com/cloud/answer/9110914) ($15,000 to $75,000) for this. You can read more about this [here](https://www.theregister.com/2019/02/11/google_gmail_developer/).
 
-OAuth for Yandex is supported via the quick setup wizard.
+OAuth for Yandex and Yahoo is supported via the quick setup wizard.
 
 OAuth for Office 365 accounts is supported, but Microsoft does not offer OAuth for Outlook, Live and Hotmail accounts (yet?).
 
-OAuth access for Yahoo was requested, but Yahoo never responded to the request. OAuth for AOL [was deactivated](https://www.programmableweb.com/api/aol-open-auth) by AOL. Verizon owns both AOL and Yahoo, collectively named [Oath inc](https://en.wikipedia.org/wiki/Verizon_Media). So, it is reasonable to assume that OAuth is not supported by Yahoo anymore too.
-
 <br />
 
 <a name="faq112"></a>
@@ -2302,8 +2301,6 @@ FairEmail groups messages based on the standard *Message-ID*, *In-Reply-To* and
 
 When FairEmail cannot connect to an email server to receive messages, for example when the internet connection is bad or a firewall or a VPN is blocking the connection, FairEmail will wait 8, 16 and 32 seconds while keeping the device awake (=use battery power) and try again to connect. If this fails, FairEmail will schedule an alarm to retry after 15, 30 and 60 minutes and let the device sleep (=no battery usage).
 
-Between connectivity changes there is a wait of 90 seconds to give the email server the opportunity to discover the old connection is broken. This is necessary because the internet connection of a mobile device is often lost abruptly and to prevent the problem described in [this FAQ](#user-content-faq23).
-
 Note that [Android doze mode](https://developer.android.com/training/monitoring-device-state/doze-standby) does not allow to wake the device earlier than after 15 minutes.
 
 *Force sync* in the three-dots menu of the unified inbox can be used to let FairEmail attempt to reconnect without waiting.
@@ -2777,6 +2774,8 @@ Updating once a week will probably be sufficient, please see [here](https://gith
 
 Permanent deletion means that messages will *irreversibly* be lost, and to prevent this from happening accidentally, this always needs to be confirmed. Even with a confirmation, some very angry people who lost some of their messages through their own fault contacted me, which was a rather unpleasant experience :-(
 
+Advanced: the IMAP delete flag in combination with the EXPUNGE command is not supportable because both email servers and not all people can handle this, risking unexpected loss of messages. A complicating factor is that not all email servers support [UID EXPUNGE](https://tools.ietf.org/html/rfc4315).
+
 <br />
 
 <a name="faq161"></a>
diff --git a/docs/FAQ-sv-rSE.md b/docs/FAQ-sv-rSE.md
index d689c92440..f97f1b7cbb 100644
--- a/docs/FAQ-sv-rSE.md
+++ b/docs/FAQ-sv-rSE.md
@@ -78,6 +78,7 @@ Relaterade frågor:
 * En förhandsvisning av ett meddelande visas inte (alltid) på Samsung klockor eftersom [setLocalOnly](https://developer.android.com/reference/androidx/core/app/NotificationCompat.Builder.html#setLocalOnly(boolean)) verkar ignoreras. Meddelande förhandsgranskningstexter är kända för att visas korrekt på Pebble 2, Fitbit Charge 3, Mi band 3 och Xiaomi Amazfit BIP wearables. Se även [denna FAQ](#user-content-faq126).
 * En [bugg i Android 6.0](https://issuetracker.google.com/issues/37068143) orsakar en krasch med *... Ogiltig offset: ... Giltigt intervall är ...* när text är markerad och knackar utanför den valda texten. Detta fel har rättats i Android 6.0.1.
 * Interna (ankare) länkar kommer inte att fungera eftersom ursprungliga meddelanden visas i en inbäddad WebView i en rullande vy (meddelandelistan). Detta är en Android-begränsning som inte kan lösas eller arbetas runt.
+* Språkdetektering [fungerar inte längre](https://issuetracker.google.com/issues/173337263) på Pixelenheter med (uppgraderat till?) Android 11
 
 ## Planerade funktioner
 
@@ -861,7 +862,7 @@ The error *... Connection refused ...* means that the email server or something
 
 The error *... Network unreachable ...* means that the email server was not reachable via the current internet connection, for example because internet traffic is restricted to local traffic only.
 
-The error *... Host is unresolved ...* or "*... Unable to resolve host ...* means that the address of the email server could not be resolved. This might be caused by ad blocking or an unreachable or not properly working [DNS](https://en.wikipedia.org/wiki/Domain_Name_System) server.
+The error *... Host is unresolved ...*, *... Unable to resolve host ...* or *... No address associated with hostname ...* means that the address of the email server could not be resolved into an IP address. This might be caused by a VPN, ad blocking or an unreachable or not properly working (local) [DNS](https://en.wikipedia.org/wiki/Domain_Name_System) server.
 
 The error *... Software caused connection abort ...* means that the email server or something between FairEmail and the email server actively terminated an existing connection. This can for example happen when connectivity was abruptly lost. A typical example is turning on flight mode.
 
@@ -2162,14 +2163,12 @@ Disabling *Partial fetch* will result in more memory usage.
 <a name="faq111"></a>
 **(111) Is OAuth supported?**
 
-OAuth for Gmail is supported via the quick setup wizard. The Android account manager will be used to fetch and refresh OAuth tokens for selected on-device accounts. OAuth for non on-device accounts is not supported because Google requires a [yearly security audit](https://support.google.com/cloud/answer/9110914) ($15,000 to $75,000) for this.
+OAuth for Gmail is supported via the quick setup wizard. The Android account manager will be used to fetch and refresh OAuth tokens for selected on-device accounts. OAuth for non on-device accounts is not supported because Google requires a [yearly security audit](https://support.google.com/cloud/answer/9110914) ($15,000 to $75,000) for this. You can read more about this [here](https://www.theregister.com/2019/02/11/google_gmail_developer/).
 
-OAuth for Yandex is supported via the quick setup wizard.
+OAuth for Yandex and Yahoo is supported via the quick setup wizard.
 
 OAuth for Office 365 accounts is supported, but Microsoft does not offer OAuth for Outlook, Live and Hotmail accounts (yet?).
 
-OAuth access for Yahoo was requested, but Yahoo never responded to the request. OAuth for AOL [was deactivated](https://www.programmableweb.com/api/aol-open-auth) by AOL. Verizon owns both AOL and Yahoo, collectively named [Oath inc](https://en.wikipedia.org/wiki/Verizon_Media). So, it is reasonable to assume that OAuth is not supported by Yahoo anymore too.
-
 <br />
 
 <a name="faq112"></a>
@@ -2302,8 +2301,6 @@ FairEmail groups messages based on the standard *Message-ID*, *In-Reply-To* and
 
 When FairEmail cannot connect to an email server to receive messages, for example when the internet connection is bad or a firewall or a VPN is blocking the connection, FairEmail will wait 8, 16 and 32 seconds while keeping the device awake (=use battery power) and try again to connect. If this fails, FairEmail will schedule an alarm to retry after 15, 30 and 60 minutes and let the device sleep (=no battery usage).
 
-Between connectivity changes there is a wait of 90 seconds to give the email server the opportunity to discover the old connection is broken. This is necessary because the internet connection of a mobile device is often lost abruptly and to prevent the problem described in [this FAQ](#user-content-faq23).
-
 Note that [Android doze mode](https://developer.android.com/training/monitoring-device-state/doze-standby) does not allow to wake the device earlier than after 15 minutes.
 
 *Force sync* in the three-dots menu of the unified inbox can be used to let FairEmail attempt to reconnect without waiting.
@@ -2777,6 +2774,8 @@ Updating once a week will probably be sufficient, please see [here](https://gith
 
 Permanent deletion means that messages will *irreversibly* be lost, and to prevent this from happening accidentally, this always needs to be confirmed. Even with a confirmation, some very angry people who lost some of their messages through their own fault contacted me, which was a rather unpleasant experience :-(
 
+Advanced: the IMAP delete flag in combination with the EXPUNGE command is not supportable because both email servers and not all people can handle this, risking unexpected loss of messages. A complicating factor is that not all email servers support [UID EXPUNGE](https://tools.ietf.org/html/rfc4315).
+
 <br />
 
 <a name="faq161"></a>
diff --git a/docs/FAQ-ta-rIN.md b/docs/FAQ-ta-rIN.md
index 7b7b451250..a593607a58 100644
--- a/docs/FAQ-ta-rIN.md
+++ b/docs/FAQ-ta-rIN.md
@@ -78,6 +78,7 @@ Related questions:
 * A preview of a message text doesn't (always) appear on Samsung watches because [setLocalOnly](https://developer.android.com/reference/androidx/core/app/NotificationCompat.Builder.html#setLocalOnly(boolean)) seem to be ignored. Message preview texts are known to be displayed correctly on Pebble 2, Fitbit Charge 3, Mi band 3, and Xiaomi Amazfit BIP wearables. See also [this FAQ](#user-content-faq126).
 * A [bug in Android 6.0](https://issuetracker.google.com/issues/37068143) causes a crash with *... Invalid offset: ... Valid range is ...* when text is selected and tapping outside of the selected text. This bug has been fixed in Android 6.0.1.
 * Internal (anchor) links will not work because original messages are shown in an embedded WebView in a scrolling view (the conversation list). This is an Android limitation which cannot be fixed or worked around.
+* Language detection [is not working anymore](https://issuetracker.google.com/issues/173337263) on Pixel devices with (upgraded to?) Android 11
 
 ## Planned features
 
@@ -861,7 +862,7 @@ The error *... Connection refused ...* means that the email server or something
 
 The error *... Network unreachable ...* means that the email server was not reachable via the current internet connection, for example because internet traffic is restricted to local traffic only.
 
-The error *... Host is unresolved ...* or "*... Unable to resolve host ...* means that the address of the email server could not be resolved. This might be caused by ad blocking or an unreachable or not properly working [DNS](https://en.wikipedia.org/wiki/Domain_Name_System) server.
+The error *... Host is unresolved ...*, *... Unable to resolve host ...* or *... No address associated with hostname ...* means that the address of the email server could not be resolved into an IP address. This might be caused by a VPN, ad blocking or an unreachable or not properly working (local) [DNS](https://en.wikipedia.org/wiki/Domain_Name_System) server.
 
 The error *... Software caused connection abort ...* means that the email server or something between FairEmail and the email server actively terminated an existing connection. This can for example happen when connectivity was abruptly lost. A typical example is turning on flight mode.
 
@@ -2162,14 +2163,12 @@ Disabling *Partial fetch* will result in more memory usage.
 <a name="faq111"></a>
 **(111) Is OAuth supported?**
 
-OAuth for Gmail is supported via the quick setup wizard. The Android account manager will be used to fetch and refresh OAuth tokens for selected on-device accounts. OAuth for non on-device accounts is not supported because Google requires a [yearly security audit](https://support.google.com/cloud/answer/9110914) ($15,000 to $75,000) for this.
+OAuth for Gmail is supported via the quick setup wizard. The Android account manager will be used to fetch and refresh OAuth tokens for selected on-device accounts. OAuth for non on-device accounts is not supported because Google requires a [yearly security audit](https://support.google.com/cloud/answer/9110914) ($15,000 to $75,000) for this. You can read more about this [here](https://www.theregister.com/2019/02/11/google_gmail_developer/).
 
-OAuth for Yandex is supported via the quick setup wizard.
+OAuth for Yandex and Yahoo is supported via the quick setup wizard.
 
 OAuth for Office 365 accounts is supported, but Microsoft does not offer OAuth for Outlook, Live and Hotmail accounts (yet?).
 
-OAuth access for Yahoo was requested, but Yahoo never responded to the request. OAuth for AOL [was deactivated](https://www.programmableweb.com/api/aol-open-auth) by AOL. Verizon owns both AOL and Yahoo, collectively named [Oath inc](https://en.wikipedia.org/wiki/Verizon_Media). So, it is reasonable to assume that OAuth is not supported by Yahoo anymore too.
-
 <br />
 
 <a name="faq112"></a>
@@ -2302,8 +2301,6 @@ FairEmail groups messages based on the standard *Message-ID*, *In-Reply-To* and
 
 When FairEmail cannot connect to an email server to receive messages, for example when the internet connection is bad or a firewall or a VPN is blocking the connection, FairEmail will wait 8, 16 and 32 seconds while keeping the device awake (=use battery power) and try again to connect. If this fails, FairEmail will schedule an alarm to retry after 15, 30 and 60 minutes and let the device sleep (=no battery usage).
 
-Between connectivity changes there is a wait of 90 seconds to give the email server the opportunity to discover the old connection is broken. This is necessary because the internet connection of a mobile device is often lost abruptly and to prevent the problem described in [this FAQ](#user-content-faq23).
-
 Note that [Android doze mode](https://developer.android.com/training/monitoring-device-state/doze-standby) does not allow to wake the device earlier than after 15 minutes.
 
 *Force sync* in the three-dots menu of the unified inbox can be used to let FairEmail attempt to reconnect without waiting.
@@ -2777,6 +2774,8 @@ Updating once a week will probably be sufficient, please see [here](https://gith
 
 Permanent deletion means that messages will *irreversibly* be lost, and to prevent this from happening accidentally, this always needs to be confirmed. Even with a confirmation, some very angry people who lost some of their messages through their own fault contacted me, which was a rather unpleasant experience :-(
 
+Advanced: the IMAP delete flag in combination with the EXPUNGE command is not supportable because both email servers and not all people can handle this, risking unexpected loss of messages. A complicating factor is that not all email servers support [UID EXPUNGE](https://tools.ietf.org/html/rfc4315).
+
 <br />
 
 <a name="faq161"></a>
diff --git a/docs/FAQ-tr-rTR.md b/docs/FAQ-tr-rTR.md
index 3e125c8153..f6a1baa6d9 100644
--- a/docs/FAQ-tr-rTR.md
+++ b/docs/FAQ-tr-rTR.md
@@ -78,6 +78,7 @@ Sıkça rastlanan hata iletileri ve çözümleri için [burayı](#user-content-f
 * A preview of a message text doesn't (always) appear on Samsung watches because [setLocalOnly](https://developer.android.com/reference/androidx/core/app/NotificationCompat.Builder.html#setLocalOnly(boolean)) seem to be ignored. Message preview texts are known to be displayed correctly on Pebble 2, Fitbit Charge 3, Mi band 3, and Xiaomi Amazfit BIP wearables. See also [this FAQ](#user-content-faq126).
 * A [bug in Android 6.0](https://issuetracker.google.com/issues/37068143) causes a crash with *... Invalid offset: ... Valid range is ...* when text is selected and tapping outside of the selected text. This bug has been fixed in Android 6.0.1.
 * Internal (anchor) links will not work because original messages are shown in an embedded WebView in a scrolling view (the conversation list). This is an Android limitation which cannot be fixed or worked around.
+* Language detection [is not working anymore](https://issuetracker.google.com/issues/173337263) on Pixel devices with (upgraded to?) Android 11
 
 ## Planlanan özellikler
 
@@ -861,7 +862,7 @@ The error *... Connection refused ...* means that the email server or something
 
 The error *... Network unreachable ...* means that the email server was not reachable via the current internet connection, for example because internet traffic is restricted to local traffic only.
 
-The error *... Host is unresolved ...* or "*... Unable to resolve host ...* means that the address of the email server could not be resolved. This might be caused by ad blocking or an unreachable or not properly working [DNS](https://en.wikipedia.org/wiki/Domain_Name_System) server.
+The error *... Host is unresolved ...*, *... Unable to resolve host ...* or *... No address associated with hostname ...* means that the address of the email server could not be resolved into an IP address. This might be caused by a VPN, ad blocking or an unreachable or not properly working (local) [DNS](https://en.wikipedia.org/wiki/Domain_Name_System) server.
 
 The error *... Software caused connection abort ...* means that the email server or something between FairEmail and the email server actively terminated an existing connection. This can for example happen when connectivity was abruptly lost. A typical example is turning on flight mode.
 
@@ -2162,14 +2163,12 @@ Disabling *Partial fetch* will result in more memory usage.
 <a name="faq111"></a>
 **(111) Is OAuth supported?**
 
-OAuth for Gmail is supported via the quick setup wizard. The Android account manager will be used to fetch and refresh OAuth tokens for selected on-device accounts. OAuth for non on-device accounts is not supported because Google requires a [yearly security audit](https://support.google.com/cloud/answer/9110914) ($15,000 to $75,000) for this.
+OAuth for Gmail is supported via the quick setup wizard. The Android account manager will be used to fetch and refresh OAuth tokens for selected on-device accounts. OAuth for non on-device accounts is not supported because Google requires a [yearly security audit](https://support.google.com/cloud/answer/9110914) ($15,000 to $75,000) for this. You can read more about this [here](https://www.theregister.com/2019/02/11/google_gmail_developer/).
 
-OAuth for Yandex is supported via the quick setup wizard.
+OAuth for Yandex and Yahoo is supported via the quick setup wizard.
 
 OAuth for Office 365 accounts is supported, but Microsoft does not offer OAuth for Outlook, Live and Hotmail accounts (yet?).
 
-OAuth access for Yahoo was requested, but Yahoo never responded to the request. OAuth for AOL [was deactivated](https://www.programmableweb.com/api/aol-open-auth) by AOL. Verizon owns both AOL and Yahoo, collectively named [Oath inc](https://en.wikipedia.org/wiki/Verizon_Media). So, it is reasonable to assume that OAuth is not supported by Yahoo anymore too.
-
 <br />
 
 <a name="faq112"></a>
@@ -2302,8 +2301,6 @@ FairEmail groups messages based on the standard *Message-ID*, *In-Reply-To* and
 
 When FairEmail cannot connect to an email server to receive messages, for example when the internet connection is bad or a firewall or a VPN is blocking the connection, FairEmail will wait 8, 16 and 32 seconds while keeping the device awake (=use battery power) and try again to connect. If this fails, FairEmail will schedule an alarm to retry after 15, 30 and 60 minutes and let the device sleep (=no battery usage).
 
-Between connectivity changes there is a wait of 90 seconds to give the email server the opportunity to discover the old connection is broken. This is necessary because the internet connection of a mobile device is often lost abruptly and to prevent the problem described in [this FAQ](#user-content-faq23).
-
 Note that [Android doze mode](https://developer.android.com/training/monitoring-device-state/doze-standby) does not allow to wake the device earlier than after 15 minutes.
 
 *Force sync* in the three-dots menu of the unified inbox can be used to let FairEmail attempt to reconnect without waiting.
@@ -2777,6 +2774,8 @@ Updating once a week will probably be sufficient, please see [here](https://gith
 
 Permanent deletion means that messages will *irreversibly* be lost, and to prevent this from happening accidentally, this always needs to be confirmed. Even with a confirmation, some very angry people who lost some of their messages through their own fault contacted me, which was a rather unpleasant experience :-(
 
+Advanced: the IMAP delete flag in combination with the EXPUNGE command is not supportable because both email servers and not all people can handle this, risking unexpected loss of messages. A complicating factor is that not all email servers support [UID EXPUNGE](https://tools.ietf.org/html/rfc4315).
+
 <br />
 
 <a name="faq161"></a>
diff --git a/docs/FAQ-uk-rUA.md b/docs/FAQ-uk-rUA.md
index 6b5aa02e6d..7056e1efe4 100644
--- a/docs/FAQ-uk-rUA.md
+++ b/docs/FAQ-uk-rUA.md
@@ -78,6 +78,7 @@
 * A preview of a message text doesn't (always) appear on Samsung watches because [setLocalOnly](https://developer.android.com/reference/androidx/core/app/NotificationCompat.Builder.html#setLocalOnly(boolean)) seem to be ignored. Message preview texts are known to be displayed correctly on Pebble 2, Fitbit Charge 3, Mi band 3, and Xiaomi Amazfit BIP wearables. See also [this FAQ](#user-content-faq126).
 * A [bug in Android 6.0](https://issuetracker.google.com/issues/37068143) causes a crash with *... Invalid offset: ... Valid range is ...* when text is selected and tapping outside of the selected text. This bug has been fixed in Android 6.0.1.
 * Internal (anchor) links will not work because original messages are shown in an embedded WebView in a scrolling view (the conversation list). This is an Android limitation which cannot be fixed or worked around.
+* Language detection [is not working anymore](https://issuetracker.google.com/issues/173337263) on Pixel devices with (upgraded to?) Android 11
 
 ## Planned features
 
@@ -861,7 +862,7 @@ The error *... Connection refused ...* means that the email server or something
 
 The error *... Network unreachable ...* means that the email server was not reachable via the current internet connection, for example because internet traffic is restricted to local traffic only.
 
-The error *... Host is unresolved ...* or "*... Unable to resolve host ...* means that the address of the email server could not be resolved. This might be caused by ad blocking or an unreachable or not properly working [DNS](https://en.wikipedia.org/wiki/Domain_Name_System) server.
+The error *... Host is unresolved ...*, *... Unable to resolve host ...* or *... No address associated with hostname ...* means that the address of the email server could not be resolved into an IP address. This might be caused by a VPN, ad blocking or an unreachable or not properly working (local) [DNS](https://en.wikipedia.org/wiki/Domain_Name_System) server.
 
 The error *... Software caused connection abort ...* means that the email server or something between FairEmail and the email server actively terminated an existing connection. This can for example happen when connectivity was abruptly lost. A typical example is turning on flight mode.
 
@@ -2162,14 +2163,12 @@ Disabling *Partial fetch* will result in more memory usage.
 <a name="faq111"></a>
 **(111) Is OAuth supported?**
 
-OAuth for Gmail is supported via the quick setup wizard. The Android account manager will be used to fetch and refresh OAuth tokens for selected on-device accounts. OAuth for non on-device accounts is not supported because Google requires a [yearly security audit](https://support.google.com/cloud/answer/9110914) ($15,000 to $75,000) for this.
+OAuth for Gmail is supported via the quick setup wizard. The Android account manager will be used to fetch and refresh OAuth tokens for selected on-device accounts. OAuth for non on-device accounts is not supported because Google requires a [yearly security audit](https://support.google.com/cloud/answer/9110914) ($15,000 to $75,000) for this. You can read more about this [here](https://www.theregister.com/2019/02/11/google_gmail_developer/).
 
-OAuth for Yandex is supported via the quick setup wizard.
+OAuth for Yandex and Yahoo is supported via the quick setup wizard.
 
 OAuth for Office 365 accounts is supported, but Microsoft does not offer OAuth for Outlook, Live and Hotmail accounts (yet?).
 
-OAuth access for Yahoo was requested, but Yahoo never responded to the request. OAuth for AOL [was deactivated](https://www.programmableweb.com/api/aol-open-auth) by AOL. Verizon owns both AOL and Yahoo, collectively named [Oath inc](https://en.wikipedia.org/wiki/Verizon_Media). So, it is reasonable to assume that OAuth is not supported by Yahoo anymore too.
-
 <br />
 
 <a name="faq112"></a>
@@ -2302,8 +2301,6 @@ FairEmail groups messages based on the standard *Message-ID*, *In-Reply-To* and
 
 When FairEmail cannot connect to an email server to receive messages, for example when the internet connection is bad or a firewall or a VPN is blocking the connection, FairEmail will wait 8, 16 and 32 seconds while keeping the device awake (=use battery power) and try again to connect. If this fails, FairEmail will schedule an alarm to retry after 15, 30 and 60 minutes and let the device sleep (=no battery usage).
 
-Between connectivity changes there is a wait of 90 seconds to give the email server the opportunity to discover the old connection is broken. This is necessary because the internet connection of a mobile device is often lost abruptly and to prevent the problem described in [this FAQ](#user-content-faq23).
-
 Note that [Android doze mode](https://developer.android.com/training/monitoring-device-state/doze-standby) does not allow to wake the device earlier than after 15 minutes.
 
 *Force sync* in the three-dots menu of the unified inbox can be used to let FairEmail attempt to reconnect without waiting.
@@ -2777,6 +2774,8 @@ Updating once a week will probably be sufficient, please see [here](https://gith
 
 Permanent deletion means that messages will *irreversibly* be lost, and to prevent this from happening accidentally, this always needs to be confirmed. Even with a confirmation, some very angry people who lost some of their messages through their own fault contacted me, which was a rather unpleasant experience :-(
 
+Advanced: the IMAP delete flag in combination with the EXPUNGE command is not supportable because both email servers and not all people can handle this, risking unexpected loss of messages. A complicating factor is that not all email servers support [UID EXPUNGE](https://tools.ietf.org/html/rfc4315).
+
 <br />
 
 <a name="faq161"></a>
diff --git a/docs/FAQ-vi-rVN.md b/docs/FAQ-vi-rVN.md
index 7b7b451250..a593607a58 100644
--- a/docs/FAQ-vi-rVN.md
+++ b/docs/FAQ-vi-rVN.md
@@ -78,6 +78,7 @@ Related questions:
 * A preview of a message text doesn't (always) appear on Samsung watches because [setLocalOnly](https://developer.android.com/reference/androidx/core/app/NotificationCompat.Builder.html#setLocalOnly(boolean)) seem to be ignored. Message preview texts are known to be displayed correctly on Pebble 2, Fitbit Charge 3, Mi band 3, and Xiaomi Amazfit BIP wearables. See also [this FAQ](#user-content-faq126).
 * A [bug in Android 6.0](https://issuetracker.google.com/issues/37068143) causes a crash with *... Invalid offset: ... Valid range is ...* when text is selected and tapping outside of the selected text. This bug has been fixed in Android 6.0.1.
 * Internal (anchor) links will not work because original messages are shown in an embedded WebView in a scrolling view (the conversation list). This is an Android limitation which cannot be fixed or worked around.
+* Language detection [is not working anymore](https://issuetracker.google.com/issues/173337263) on Pixel devices with (upgraded to?) Android 11
 
 ## Planned features
 
@@ -861,7 +862,7 @@ The error *... Connection refused ...* means that the email server or something
 
 The error *... Network unreachable ...* means that the email server was not reachable via the current internet connection, for example because internet traffic is restricted to local traffic only.
 
-The error *... Host is unresolved ...* or "*... Unable to resolve host ...* means that the address of the email server could not be resolved. This might be caused by ad blocking or an unreachable or not properly working [DNS](https://en.wikipedia.org/wiki/Domain_Name_System) server.
+The error *... Host is unresolved ...*, *... Unable to resolve host ...* or *... No address associated with hostname ...* means that the address of the email server could not be resolved into an IP address. This might be caused by a VPN, ad blocking or an unreachable or not properly working (local) [DNS](https://en.wikipedia.org/wiki/Domain_Name_System) server.
 
 The error *... Software caused connection abort ...* means that the email server or something between FairEmail and the email server actively terminated an existing connection. This can for example happen when connectivity was abruptly lost. A typical example is turning on flight mode.
 
@@ -2162,14 +2163,12 @@ Disabling *Partial fetch* will result in more memory usage.
 <a name="faq111"></a>
 **(111) Is OAuth supported?**
 
-OAuth for Gmail is supported via the quick setup wizard. The Android account manager will be used to fetch and refresh OAuth tokens for selected on-device accounts. OAuth for non on-device accounts is not supported because Google requires a [yearly security audit](https://support.google.com/cloud/answer/9110914) ($15,000 to $75,000) for this.
+OAuth for Gmail is supported via the quick setup wizard. The Android account manager will be used to fetch and refresh OAuth tokens for selected on-device accounts. OAuth for non on-device accounts is not supported because Google requires a [yearly security audit](https://support.google.com/cloud/answer/9110914) ($15,000 to $75,000) for this. You can read more about this [here](https://www.theregister.com/2019/02/11/google_gmail_developer/).
 
-OAuth for Yandex is supported via the quick setup wizard.
+OAuth for Yandex and Yahoo is supported via the quick setup wizard.
 
 OAuth for Office 365 accounts is supported, but Microsoft does not offer OAuth for Outlook, Live and Hotmail accounts (yet?).
 
-OAuth access for Yahoo was requested, but Yahoo never responded to the request. OAuth for AOL [was deactivated](https://www.programmableweb.com/api/aol-open-auth) by AOL. Verizon owns both AOL and Yahoo, collectively named [Oath inc](https://en.wikipedia.org/wiki/Verizon_Media). So, it is reasonable to assume that OAuth is not supported by Yahoo anymore too.
-
 <br />
 
 <a name="faq112"></a>
@@ -2302,8 +2301,6 @@ FairEmail groups messages based on the standard *Message-ID*, *In-Reply-To* and
 
 When FairEmail cannot connect to an email server to receive messages, for example when the internet connection is bad or a firewall or a VPN is blocking the connection, FairEmail will wait 8, 16 and 32 seconds while keeping the device awake (=use battery power) and try again to connect. If this fails, FairEmail will schedule an alarm to retry after 15, 30 and 60 minutes and let the device sleep (=no battery usage).
 
-Between connectivity changes there is a wait of 90 seconds to give the email server the opportunity to discover the old connection is broken. This is necessary because the internet connection of a mobile device is often lost abruptly and to prevent the problem described in [this FAQ](#user-content-faq23).
-
 Note that [Android doze mode](https://developer.android.com/training/monitoring-device-state/doze-standby) does not allow to wake the device earlier than after 15 minutes.
 
 *Force sync* in the three-dots menu of the unified inbox can be used to let FairEmail attempt to reconnect without waiting.
@@ -2777,6 +2774,8 @@ Updating once a week will probably be sufficient, please see [here](https://gith
 
 Permanent deletion means that messages will *irreversibly* be lost, and to prevent this from happening accidentally, this always needs to be confirmed. Even with a confirmation, some very angry people who lost some of their messages through their own fault contacted me, which was a rather unpleasant experience :-(
 
+Advanced: the IMAP delete flag in combination with the EXPUNGE command is not supportable because both email servers and not all people can handle this, risking unexpected loss of messages. A complicating factor is that not all email servers support [UID EXPUNGE](https://tools.ietf.org/html/rfc4315).
+
 <br />
 
 <a name="faq161"></a>
diff --git a/docs/FAQ-zh-rCN.md b/docs/FAQ-zh-rCN.md
index 44ae7ba6ca..5e3b7e0dd6 100644
--- a/docs/FAQ-zh-rCN.md
+++ b/docs/FAQ-zh-rCN.md
@@ -77,7 +77,8 @@
 * Scrolling to an internally linked location in original messages does not work. Scrolling to an internally linked location in original messages does not work. This can't be fixed because the original message view is contained in a scrolling view.
 * A preview of a message text doesn't (always) appear on Samsung watches because [setLocalOnly](https://developer.android.com/reference/androidx/core/app/NotificationCompat.Builder.html#setLocalOnly(boolean)) seem to be ignored. Message preview texts are known to be displayed correctly on Pebble 2, Fitbit Charge 3, and Mi band 3 wearables. See also [this FAQ](#user-content-faq126). Message preview texts are known to be displayed correctly on Pebble 2, Fitbit Charge 3, Mi band 3, and Xiaomi Amazfit BIP wearables. See also [this FAQ](#user-content-faq126).
 * A [bug in Android 6.0](https://issuetracker.google.com/issues/37068143) causes a crash with *... Invalid offset: ... Valid range is ...* when text is selected and tapping outside of the selected text. This bug has been fixed in Android 6.0.1. Invalid offset: ... Valid range is ...</em> when text is selected and tapping outside of the selected text. This bug has been fixed in Android 6.0.1.
-* Internal (anchor) links will not work because original messages are shown in an embedded WebView in a scrolling view (the conversation list). This is an Android limitation which cannot be fixed or worked around. This is an Android limitation which cannot be fixed or worked around.</ul>
+* Internal (anchor) links will not work because original messages are shown in an embedded WebView in a scrolling view (the conversation list). This is an Android limitation which cannot be fixed or worked around. This is an Android limitation which cannot be fixed or worked around.
+* Language detection [is not working anymore](https://issuetracker.google.com/issues/173337263) on Pixel devices with (upgraded to?) Android 11</ul>
 
 ## 计划添加的功能
 
@@ -861,7 +862,7 @@ The error *... Connection refused ...* means that the email server or something
 
 The error *... Network unreachable ...* means that the email server was not reachable via the current internet connection, for example because internet traffic is restricted to local traffic only.
 
-The error *... Host is unresolved ...* or "*... Unable to resolve host ...* means that the address of the email server could not be resolved. This might be caused by ad blocking or an unreachable or not properly working [DNS](https://en.wikipedia.org/wiki/Domain_Name_System) server.
+The error *... Host is unresolved ...*, *... Unable to resolve host ...* or *... No address associated with hostname ...* means that the address of the email server could not be resolved into an IP address. This might be caused by a VPN, ad blocking or an unreachable or not properly working (local) [DNS](https://en.wikipedia.org/wiki/Domain_Name_System) server.
 
 The error *... Software caused connection abort ...* means that the email server or something between FairEmail and the email server actively terminated an existing connection. This can for example happen when connectivity was abruptly lost. A typical example is turning on flight mode.
 
@@ -2162,14 +2163,12 @@ Disabling *Partial fetch* will result in more memory usage.
 <a name="faq111"></a>
 **(111) Is OAuth supported?**
 
-OAuth for Gmail is supported via the quick setup wizard. The Android account manager will be used to fetch and refresh OAuth tokens for selected on-device accounts. OAuth for non on-device accounts is not supported because Google requires a [yearly security audit](https://support.google.com/cloud/answer/9110914) ($15,000 to $75,000) for this.
+OAuth for Gmail is supported via the quick setup wizard. The Android account manager will be used to fetch and refresh OAuth tokens for selected on-device accounts. OAuth for non on-device accounts is not supported because Google requires a [yearly security audit](https://support.google.com/cloud/answer/9110914) ($15,000 to $75,000) for this. You can read more about this [here](https://www.theregister.com/2019/02/11/google_gmail_developer/).
 
-OAuth for Yandex is supported via the quick setup wizard.
+OAuth for Yandex and Yahoo is supported via the quick setup wizard.
 
 OAuth for Office 365 accounts is supported, but Microsoft does not offer OAuth for Outlook, Live and Hotmail accounts (yet?).
 
-OAuth access for Yahoo was requested, but Yahoo never responded to the request. OAuth for AOL [was deactivated](https://www.programmableweb.com/api/aol-open-auth) by AOL. Verizon owns both AOL and Yahoo, collectively named [Oath inc](https://en.wikipedia.org/wiki/Verizon_Media). So, it is reasonable to assume that OAuth is not supported by Yahoo anymore too.
-
 <br />
 
 <a name="faq112"></a>
@@ -2302,8 +2301,6 @@ FairEmail groups messages based on the standard *Message-ID*, *In-Reply-To* and
 
 When FairEmail cannot connect to an email server to receive messages, for example when the internet connection is bad or a firewall or a VPN is blocking the connection, FairEmail will wait 8, 16 and 32 seconds while keeping the device awake (=use battery power) and try again to connect. If this fails, FairEmail will schedule an alarm to retry after 15, 30 and 60 minutes and let the device sleep (=no battery usage).
 
-Between connectivity changes there is a wait of 90 seconds to give the email server the opportunity to discover the old connection is broken. This is necessary because the internet connection of a mobile device is often lost abruptly and to prevent the problem described in [this FAQ](#user-content-faq23).
-
 Note that [Android doze mode](https://developer.android.com/training/monitoring-device-state/doze-standby) does not allow to wake the device earlier than after 15 minutes.
 
 *Force sync* in the three-dots menu of the unified inbox can be used to let FairEmail attempt to reconnect without waiting.
@@ -2777,6 +2774,8 @@ Updating once a week will probably be sufficient, please see [here](https://gith
 
 Permanent deletion means that messages will *irreversibly* be lost, and to prevent this from happening accidentally, this always needs to be confirmed. Even with a confirmation, some very angry people who lost some of their messages through their own fault contacted me, which was a rather unpleasant experience :-(
 
+Advanced: the IMAP delete flag in combination with the EXPUNGE command is not supportable because both email servers and not all people can handle this, risking unexpected loss of messages. A complicating factor is that not all email servers support [UID EXPUNGE](https://tools.ietf.org/html/rfc4315).
+
 <br />
 
 <a name="faq161"></a>
diff --git a/docs/FAQ-zh-rTW.md b/docs/FAQ-zh-rTW.md
index 97abb9d1fd..8770ef55bb 100644
--- a/docs/FAQ-zh-rTW.md
+++ b/docs/FAQ-zh-rTW.md
@@ -78,6 +78,7 @@ Related questions:
 * A preview of a message text doesn't (always) appear on Samsung watches because [setLocalOnly](https://developer.android.com/reference/androidx/core/app/NotificationCompat.Builder.html#setLocalOnly(boolean)) seem to be ignored. Message preview texts are known to be displayed correctly on Pebble 2, Fitbit Charge 3, Mi band 3, and Xiaomi Amazfit BIP wearables. See also [this FAQ](#user-content-faq126).
 * A [bug in Android 6.0](https://issuetracker.google.com/issues/37068143) causes a crash with *... Invalid offset: ... Valid range is ...* when text is selected and tapping outside of the selected text. This bug has been fixed in Android 6.0.1.
 * Internal (anchor) links will not work because original messages are shown in an embedded WebView in a scrolling view (the conversation list). This is an Android limitation which cannot be fixed or worked around.
+* Language detection [is not working anymore](https://issuetracker.google.com/issues/173337263) on Pixel devices with (upgraded to?) Android 11
 
 ## Planned features
 
@@ -861,7 +862,7 @@ The error *... Connection refused ...* means that the email server or something
 
 The error *... Network unreachable ...* means that the email server was not reachable via the current internet connection, for example because internet traffic is restricted to local traffic only.
 
-The error *... Host is unresolved ...* or "*... Unable to resolve host ...* means that the address of the email server could not be resolved. This might be caused by ad blocking or an unreachable or not properly working [DNS](https://en.wikipedia.org/wiki/Domain_Name_System) server.
+The error *... Host is unresolved ...*, *... Unable to resolve host ...* or *... No address associated with hostname ...* means that the address of the email server could not be resolved into an IP address. This might be caused by a VPN, ad blocking or an unreachable or not properly working (local) [DNS](https://en.wikipedia.org/wiki/Domain_Name_System) server.
 
 The error *... Software caused connection abort ...* means that the email server or something between FairEmail and the email server actively terminated an existing connection. This can for example happen when connectivity was abruptly lost. A typical example is turning on flight mode.
 
@@ -2162,14 +2163,12 @@ Disabling *Partial fetch* will result in more memory usage.
 <a name="faq111"></a>
 **(111) Is OAuth supported?**
 
-OAuth for Gmail is supported via the quick setup wizard. The Android account manager will be used to fetch and refresh OAuth tokens for selected on-device accounts. OAuth for non on-device accounts is not supported because Google requires a [yearly security audit](https://support.google.com/cloud/answer/9110914) ($15,000 to $75,000) for this.
+OAuth for Gmail is supported via the quick setup wizard. The Android account manager will be used to fetch and refresh OAuth tokens for selected on-device accounts. OAuth for non on-device accounts is not supported because Google requires a [yearly security audit](https://support.google.com/cloud/answer/9110914) ($15,000 to $75,000) for this. You can read more about this [here](https://www.theregister.com/2019/02/11/google_gmail_developer/).
 
-OAuth for Yandex is supported via the quick setup wizard.
+OAuth for Yandex and Yahoo is supported via the quick setup wizard.
 
 OAuth for Office 365 accounts is supported, but Microsoft does not offer OAuth for Outlook, Live and Hotmail accounts (yet?).
 
-OAuth access for Yahoo was requested, but Yahoo never responded to the request. OAuth for AOL [was deactivated](https://www.programmableweb.com/api/aol-open-auth) by AOL. Verizon owns both AOL and Yahoo, collectively named [Oath inc](https://en.wikipedia.org/wiki/Verizon_Media). So, it is reasonable to assume that OAuth is not supported by Yahoo anymore too.
-
 <br />
 
 <a name="faq112"></a>
@@ -2302,8 +2301,6 @@ FairEmail groups messages based on the standard *Message-ID*, *In-Reply-To* and
 
 When FairEmail cannot connect to an email server to receive messages, for example when the internet connection is bad or a firewall or a VPN is blocking the connection, FairEmail will wait 8, 16 and 32 seconds while keeping the device awake (=use battery power) and try again to connect. If this fails, FairEmail will schedule an alarm to retry after 15, 30 and 60 minutes and let the device sleep (=no battery usage).
 
-Between connectivity changes there is a wait of 90 seconds to give the email server the opportunity to discover the old connection is broken. This is necessary because the internet connection of a mobile device is often lost abruptly and to prevent the problem described in [this FAQ](#user-content-faq23).
-
 Note that [Android doze mode](https://developer.android.com/training/monitoring-device-state/doze-standby) does not allow to wake the device earlier than after 15 minutes.
 
 *Force sync* in the three-dots menu of the unified inbox can be used to let FairEmail attempt to reconnect without waiting.
@@ -2777,6 +2774,8 @@ Updating once a week will probably be sufficient, please see [here](https://gith
 
 Permanent deletion means that messages will *irreversibly* be lost, and to prevent this from happening accidentally, this always needs to be confirmed. Even with a confirmation, some very angry people who lost some of their messages through their own fault contacted me, which was a rather unpleasant experience :-(
 
+Advanced: the IMAP delete flag in combination with the EXPUNGE command is not supportable because both email servers and not all people can handle this, risking unexpected loss of messages. A complicating factor is that not all email servers support [UID EXPUNGE](https://tools.ietf.org/html/rfc4315).
+
 <br />
 
 <a name="faq161"></a>