* Rich text editor: besides that very few people would use this on a small mobile device, Android doesn't support a rich text editor and most rich text editor open source projects are abandoned.
* Executing filter rules: filter rules should be executed on the server because a battery powered device with possibly an unstable internet connection is not suitable for this.
* Shortcut frequently contacted: Android [doesn't support this anymore](https://developer.android.com/guide/topics/providers/contacts-provider#ObsoleteData).
* Switch language: although it is possible to change the language of an app, Android is not designed for this. Better fix the translation in your language if needed, see [this FAQ](#user-content-faq26) about how to.
* Notification per account: this would result in multiple icons in the status bar and most people don't like this. Note that the account colors are shown in the notifications too.
Background: this is necessary because of the introduction of [doze mode](https://developer.android.com/training/monitoring-device-state/doze-standby) in Android 6 Marshmallow.
Invalid security certificate: you should try to fix this by contacting your provider or by getting a valid security certificate
because invalid security certificates are insecure and allow [man-in-the-middle attacks](https://en.wikipedia.org/wiki/Man-in-the-middle_attack).
If money is an obstacle, you can get free security certificates from [Let’s Encrypt](https://letsencrypt.org).
IMAP STARTTLS: the EFF [writes](https://www.eff.org/nl/deeplinks/2018/06/announcing-starttls-everywhere-securing-hop-hop-email-delivery):
"*Additionally, even if you configure STARTTLS perfectly and use a valid certificate, there’s still no guarantee your communication will be encrypted.*"
Empty password: your username is likely easily guessed, so this is very insecure.
If you still want to use an invalid security certificate, IMAP STARTTLS or an empty password,
you'll need to enable insecure connections in the advanced settings and also in the account and/or identity settings.
Additionally, IMAP STARTTLS needs to be enabled in the account settings too.
If this doesn't work, see here for more solutions: [https://support.google.com/mail/accounts/answer/78754](https://support.google.com/mail/accounts/answer/78754)
See here for more information: [https://support.office.com/en-us/article/what-is-a-microsoft-exchange-account-47f000aa-c2bf-48ac-9bc2-83e5c6036793](https://support.office.com/en-us/article/what-is-a-microsoft-exchange-account-47f000aa-c2bf-48ac-9bc2-83e5c6036793)
The error message *UIDPLUS not supported* means that your email provider does not provide the IMAP [UIDPLUS extension](https://tools.ietf.org/html/rfc4315).
This IMAP extension is required to implement two way synchronization, which is not an optional feature.
So, unless your provider can enable this extension, you cannot use FairEmail for this provider.
You can start searching for messages on sender, recipient, subject or message text by using the magnify glass in the action bar of a folder (not in the unified inbox because it could be a collection of folders).
On some devices, where there are lots of applications competing for memory, Android may stop the synchronization service as a last resort.
Some Android versions,
in particular of Huawei (see [here](https://www.forbes.com/sites/bensin/2016/07/04/push-notifications-not-coming-through-to-your-huawei-phone-heres-how-to-fix-it/) for a fix)
or Xiaomi (see [here](https://www.forbes.com/sites/bensin/2016/11/17/how-to-fix-push-notifications-on-xiaomis-miui-8-for-real/) for a fix)
**(23) Why do I get 'Too many simultaneous connections' ?**
The message *Too many simultaneous connections* is sent by the email server when there are too many connections to the same email account at the same time.
Possible causes are:
* There are multiple email clients connected to the same account
* The same email client is connected multiple times to the same account
* The previous connection was terminated abruptly for example by losing internet connectivity
No app, except maybe file managers, targeting Android 4.4 KitKat or later should ask for storage permissions because it would allow access to *all* files.
**(27) Why are images shown without tapping 'Show images' ?**
There are two types of images:
* Images embedded into a message
* Images stored on a remote server
Embedded images, also visible as an attachment, are always shown, but images stored on a remote server need to be downloaded by tapping *Show images*.
Note that downloading images from a remote server can be used to record you did see a message, which you likely don't want if the message is spam or malicious.
* The 256 bit key is generated with *PBKDF2WithHmacSHA1* using a 128 bit secure random salt and 65536 iterations
* The cipher is *AES/CBC/PKCS5Padding*
<aname="faq37"></a>
**(37) How are passwords stored?**
Providers require passwords in plain text, so the background service that takes care of synchronizing messages needs to send passwords in plain text.
Since encrypting passwords would require a secret and the background service needs to know this secret, this could only be done by storing that secret.
Storing a secret together with encrypted passwords would not add anything, so passwords are stored in plain text in a safe, inaccessible place.
Normally the Android [storage access framework](https://developer.android.com/guide/topics/providers/document-provider) is used to select files and folder.
However, some file explorers can be used to select files and folders too
in which case you get a choice which app to use to select the file or folder and the choice to do this once or always.
On some Android versions selecting 'once' results in the file/folder selection to be canceled, so you will need to select 'always' for the file/folder selection to work.
If you have another question, want to request a feature or report a bug, you can use [this forum](https://forum.xda-developers.com/android/apps-games/source-email-t3824168).
