diff --git a/app/src/main/java/eu/faircode/email/EmailService.java b/app/src/main/java/eu/faircode/email/EmailService.java
index 6ca84f3356..6ce585293c 100644
--- a/app/src/main/java/eu/faircode/email/EmailService.java
+++ b/app/src/main/java/eu/faircode/email/EmailService.java
@@ -192,11 +192,13 @@ public class EmailService implements AutoCloseable {
         boolean auth_login = prefs.getBoolean("auth_login", true);
         boolean auth_ntlm = prefs.getBoolean("auth_ntlm", true);
         boolean auth_sasl = prefs.getBoolean("auth_sasl", true);
+        boolean auth_apop = prefs.getBoolean("auth_apop", false);
         Log.i("Authenticate" +
                 " plain=" + auth_plain +
                 " login=" + auth_login +
                 " ntlm=" + auth_ntlm +
-                " sasl=" + auth_sasl);
+                " sasl=" + auth_sasl +
+                " apop=" + auth_apop);
 
         properties.put("mail.event.scope", "folder");
         properties.put("mail.event.executor", executor);
@@ -207,6 +209,8 @@ public class EmailService implements AutoCloseable {
             properties.put("mail." + protocol + ".auth.login.disable", "true");
         if (!auth_ntlm)
             properties.put("mail." + protocol + ".auth.ntlm.disable", "true");
+        if (auth_apop)
+            properties.put("mail." + protocol + ".apop.enable", "true");
 
         // SASL is attempted before other authentication methods
         properties.put("mail." + protocol + ".sasl.enable", Boolean.toString(auth_sasl));
diff --git a/app/src/main/java/eu/faircode/email/FragmentOptionsMisc.java b/app/src/main/java/eu/faircode/email/FragmentOptionsMisc.java
index 4df9ec0610..ebe36e66ec 100644
--- a/app/src/main/java/eu/faircode/email/FragmentOptionsMisc.java
+++ b/app/src/main/java/eu/faircode/email/FragmentOptionsMisc.java
@@ -156,6 +156,7 @@ public class FragmentOptionsMisc extends FragmentBase implements SharedPreferenc
     private SwitchCompat swAuthLogin;
     private SwitchCompat swAuthNtlm;
     private SwitchCompat swAuthSasl;
+    private SwitchCompat swAuthApop;
     private SwitchCompat swKeepAlivePoll;
     private SwitchCompat swEmptyPool;
     private SwitchCompat swIdleDone;
@@ -196,7 +197,7 @@ public class FragmentOptionsMisc extends FragmentBase implements SharedPreferenc
             "query_threads", "wal", "checkpoints", "sqlite_cache",
             "chunk_size", "undo_manager", "webview_legacy",
             "use_modseq", "uid_command", "perform_expunge", "uid_expunge",
-            "auth_plain", "auth_login", "auth_ntlm", "auth_sasl",
+            "auth_plain", "auth_login", "auth_ntlm", "auth_sasl", "auth_apop",
             "keep_alive_poll", "empty_pool", "idle_done",
             "exact_alarms", "infra", "dup_msgids", "test_iab"
     };
@@ -305,6 +306,7 @@ public class FragmentOptionsMisc extends FragmentBase implements SharedPreferenc
         swAuthLogin = view.findViewById(R.id.swAuthLogin);
         swAuthNtlm = view.findViewById(R.id.swAuthNtlm);
         swAuthSasl = view.findViewById(R.id.swAuthSasl);
+        swAuthApop = view.findViewById(R.id.swAuthApop);
         swKeepAlivePoll = view.findViewById(R.id.swKeepAlivePoll);
         swEmptyPool = view.findViewById(R.id.swEmptyPool);
         swIdleDone = view.findViewById(R.id.swIdleDone);
@@ -1003,6 +1005,13 @@ public class FragmentOptionsMisc extends FragmentBase implements SharedPreferenc
             }
         });
 
+        swAuthApop.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {
+            @Override
+            public void onCheckedChanged(CompoundButton compoundButton, boolean checked) {
+                prefs.edit().putBoolean("auth_apop", checked).apply();
+            }
+        });
+
         swKeepAlivePoll.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {
             @Override
             public void onCheckedChanged(CompoundButton compoundButton, boolean checked) {
@@ -1528,6 +1537,7 @@ public class FragmentOptionsMisc extends FragmentBase implements SharedPreferenc
         swAuthLogin.setChecked(prefs.getBoolean("auth_login", true));
         swAuthNtlm.setChecked(prefs.getBoolean("auth_ntlm", true));
         swAuthSasl.setChecked(prefs.getBoolean("auth_sasl", true));
+        swAuthApop.setChecked(prefs.getBoolean("auth_apop", false));
         swKeepAlivePoll.setChecked(prefs.getBoolean("keep_alive_poll", false));
         swEmptyPool.setChecked(prefs.getBoolean("empty_pool", true));
         swIdleDone.setChecked(prefs.getBoolean("idle_done", true));
diff --git a/app/src/main/java/eu/faircode/email/ServiceSynchronize.java b/app/src/main/java/eu/faircode/email/ServiceSynchronize.java
index d361aa3b9e..b1d0886e99 100644
--- a/app/src/main/java/eu/faircode/email/ServiceSynchronize.java
+++ b/app/src/main/java/eu/faircode/email/ServiceSynchronize.java
@@ -155,7 +155,7 @@ public class ServiceSynchronize extends ServiceBase implements SharedPreferences
             "download_headers", "download_eml",
             "prefer_ip4", "bind_socket", "standalone_vpn", "tcp_keep_alive", "ssl_harden", "cert_strict", // force reconnect
             "experiments", "debug", "protocol", // force reconnect
-            "auth_plain", "auth_login", "auth_ntlm", "auth_sasl", // force reconnect
+            "auth_plain", "auth_login", "auth_ntlm", "auth_sasl", "auth_apop", // force reconnect
             "keep_alive_poll", "empty_pool", "idle_done", // force reconnect
             "exact_alarms" // force schedule
     ));
diff --git a/app/src/main/res/layout/fragment_options_misc.xml b/app/src/main/res/layout/fragment_options_misc.xml
index 4d9f102f58..c9803cfd84 100644
--- a/app/src/main/res/layout/fragment_options_misc.xml
+++ b/app/src/main/res/layout/fragment_options_misc.xml
@@ -980,6 +980,17 @@
                     app:layout_constraintTop_toBottomOf="@id/swAuthNtlm"
                     app:switchPadding="12dp" />
 
+                <androidx.appcompat.widget.SwitchCompat
+                    android:id="@+id/swAuthApop"
+                    android:layout_width="0dp"
+                    android:layout_height="wrap_content"
+                    android:layout_marginTop="12dp"
+                    android:text="@string/title_advanced_auth_apop"
+                    app:layout_constraintEnd_toEndOf="parent"
+                    app:layout_constraintStart_toStartOf="parent"
+                    app:layout_constraintTop_toBottomOf="@id/swAuthSasl"
+                    app:switchPadding="12dp" />
+
                 <androidx.appcompat.widget.SwitchCompat
                     android:id="@+id/swKeepAlivePoll"
                     android:layout_width="0dp"
@@ -988,7 +999,7 @@
                     android:text="@string/title_advanced_keep_alive_poll"
                     app:layout_constraintEnd_toEndOf="parent"
                     app:layout_constraintStart_toStartOf="parent"
-                    app:layout_constraintTop_toBottomOf="@id/swAuthSasl"
+                    app:layout_constraintTop_toBottomOf="@id/swAuthApop"
                     app:switchPadding="12dp" />
 
                 <androidx.appcompat.widget.SwitchCompat
diff --git a/app/src/main/res/values/strings.xml b/app/src/main/res/values/strings.xml
index c474bf6396..cf89e88c93 100644
--- a/app/src/main/res/values/strings.xml
+++ b/app/src/main/res/values/strings.xml
@@ -704,6 +704,7 @@
     <string name="title_advanced_auth_login" translatable="false">LOGIN</string>
     <string name="title_advanced_auth_ntlm" translatable="false">NTLM</string>
     <string name="title_advanced_auth_sasl" translatable="false">SASL</string>
+    <string name="title_advanced_auth_apop" translatable="false">APOP</string>
     <string name="title_advanced_idle_done" translatable="false">IDLE/DONE</string>
     <string name="title_advanced_keep_alive_poll" translatable="false">Poll on keep-alive</string>
     <string name="title_advanced_empty_pool" translatable="false">Empty connection pool</string>