diff --git a/app/src/main/java/eu/faircode/email/BoundaryCallbackMessages.java b/app/src/main/java/eu/faircode/email/BoundaryCallbackMessages.java
index 7968e7b5d6..29fbe6e4c8 100644
--- a/app/src/main/java/eu/faircode/email/BoundaryCallbackMessages.java
+++ b/app/src/main/java/eu/faircode/email/BoundaryCallbackMessages.java
@@ -282,7 +282,7 @@ public class BoundaryCallbackMessages extends PagedList.BoundaryCallback<TupleMe
 
                 Log.i("Boundary server connecting account=" + account.name);
                 istore = (IMAPStore) isession.getStore(protocol);
-                ConnectionHelper.connect(context, istore, account);
+                ConnectionHelper.connect(context, isession, istore, account);
 
                 Log.i("Boundary server opening folder=" + browsable.name);
                 ifolder = (IMAPFolder) istore.getFolder(browsable.name);
diff --git a/app/src/main/java/eu/faircode/email/ConnectionHelper.java b/app/src/main/java/eu/faircode/email/ConnectionHelper.java
index 89b8429ce1..a167a193e6 100644
--- a/app/src/main/java/eu/faircode/email/ConnectionHelper.java
+++ b/app/src/main/java/eu/faircode/email/ConnectionHelper.java
@@ -32,6 +32,8 @@ import java.util.Map;
 
 import javax.mail.Address;
 import javax.mail.MessagingException;
+import javax.mail.Session;
+import javax.mail.Transport;
 import javax.mail.internet.InternetAddress;
 
 public class ConnectionHelper {
@@ -254,8 +256,16 @@ public class ConnectionHelper {
         return true;
     }
 
-    static void connect(Context context, IMAPStore istore, EntityAccount account) throws MessagingException {
-        istore.connect(account.host, account.port, account.user, account.password);
+    static void connect(Context context, Session isession, IMAPStore istore, EntityAccount account) throws MessagingException {
+        connect(context, isession, istore, account.host, account.port, account.user, account.password);
+    }
+
+    static void connect(Context context, Session isession, Transport itransport, EntityIdentity identity) throws MessagingException {
+        connect(context, isession, itransport, identity.host, identity.port, identity.user, identity.password);
+    }
+
+    static void connect(Context context, Session isession, IMAPStore istore, String host, int port, String user, String password) throws MessagingException {
+        istore.connect(host, port, user, password);
 
         // https://www.ietf.org/rfc/rfc2971.txt
         if (istore.hasCapability("ID"))
@@ -277,6 +287,10 @@ public class ConnectionHelper {
             }
     }
 
+    static void connect(Context context, Session isession, Transport itransport, String host, int port, String user, String password) throws MessagingException {
+        itransport.connect(host, port, user, password);
+    }
+    
     static boolean airplaneMode(Context context) {
         return Settings.System.getInt(context.getContentResolver(),
                 Settings.Global.AIRPLANE_MODE_ON, 0) != 0;
diff --git a/app/src/main/java/eu/faircode/email/FragmentAccount.java b/app/src/main/java/eu/faircode/email/FragmentAccount.java
index f52cac1260..a9c5577c37 100644
--- a/app/src/main/java/eu/faircode/email/FragmentAccount.java
+++ b/app/src/main/java/eu/faircode/email/FragmentAccount.java
@@ -72,7 +72,6 @@ import java.util.Properties;
 
 import javax.mail.Folder;
 import javax.mail.Session;
-import javax.mail.Store;
 
 import static android.app.Activity.RESULT_OK;
 import static com.google.android.material.textfield.TextInputLayout.END_ICON_NONE;
@@ -536,10 +535,10 @@ public class FragmentAccount extends FragmentBase {
                 Properties props = MessageHelper.getSessionProperties(realm, insecure);
                 Session isession = Session.getInstance(props, null);
                 isession.setDebug(true);
-                try (Store istore = isession.getStore("imap" + (starttls ? "" : "s"))) {
-                    istore.connect(host, Integer.parseInt(port), user, password);
+                try (IMAPStore istore = (IMAPStore) isession.getStore("imap" + (starttls ? "" : "s"))) {
+                    ConnectionHelper.connect(context, isession, istore, host, Integer.parseInt(port), user, password);
 
-                    result.idle = ((IMAPStore) istore).hasCapability("IDLE");
+                    result.idle = istore.hasCapability("IDLE");
 
                     boolean inbox = false;
                     boolean archive = false;
@@ -893,8 +892,8 @@ public class FragmentAccount extends FragmentBase {
                     Session isession = Session.getInstance(props, null);
                     isession.setDebug(true);
 
-                    try (Store istore = isession.getStore("imap" + (starttls ? "" : "s"))) {
-                        istore.connect(host, Integer.parseInt(port), user, password);
+                    try (IMAPStore istore = (IMAPStore) isession.getStore("imap" + (starttls ? "" : "s"))) {
+                        ConnectionHelper.connect(context, isession, istore, host, Integer.parseInt(port), user, password);
 
                         for (Folder ifolder : istore.getDefaultFolder().list("*")) {
                             // Check folder attributes
diff --git a/app/src/main/java/eu/faircode/email/FragmentIdentity.java b/app/src/main/java/eu/faircode/email/FragmentIdentity.java
index 1f213adaae..3a9dd32e52 100644
--- a/app/src/main/java/eu/faircode/email/FragmentIdentity.java
+++ b/app/src/main/java/eu/faircode/email/FragmentIdentity.java
@@ -703,7 +703,7 @@ public class FragmentIdentity extends FragmentBase {
 
                     // Create transport
                     try (Transport itransport = isession.getTransport(protocol)) {
-                        itransport.connect(host, Integer.parseInt(port), user, password);
+                        ConnectionHelper.connect(context, isession, itransport, host, Integer.parseInt(port), user, password);
                     }
                 }
 
diff --git a/app/src/main/java/eu/faircode/email/FragmentOptionsMisc.java b/app/src/main/java/eu/faircode/email/FragmentOptionsMisc.java
index d1b764693f..449378747f 100644
--- a/app/src/main/java/eu/faircode/email/FragmentOptionsMisc.java
+++ b/app/src/main/java/eu/faircode/email/FragmentOptionsMisc.java
@@ -55,7 +55,6 @@ public class FragmentOptionsMisc extends FragmentBase implements SharedPreferenc
     private SwitchCompat swDoubleBack;
     private SwitchCompat swEnglish;
     private SwitchCompat swWatchdog;
-    private SwitchCompat swPreferIp4;
     private SwitchCompat swUpdates;
     private SwitchCompat swCrashReports;
     private SwitchCompat swDebug;
@@ -69,7 +68,7 @@ public class FragmentOptionsMisc extends FragmentBase implements SharedPreferenc
     private Group grpDebug;
 
     private final static String[] RESET_OPTIONS = new String[]{
-            "badge", "subscriptions", "subscribed_only", "biometrics_timeout", "double_back", "english", "watchdog", "prefer_ip4", "updates", "crash_reports", "debug"
+            "badge", "subscriptions", "subscribed_only", "biometrics_timeout", "double_back", "english", "watchdog", "updates", "crash_reports", "debug"
     };
 
     private final static String[] RESET_QUESTIONS = new String[]{
@@ -94,7 +93,6 @@ public class FragmentOptionsMisc extends FragmentBase implements SharedPreferenc
         swDoubleBack = view.findViewById(R.id.swDoubleBack);
         swEnglish = view.findViewById(R.id.swEnglish);
         swWatchdog = view.findViewById(R.id.swWatchdog);
-        swPreferIp4 = view.findViewById(R.id.swPreferIp4);
         swUpdates = view.findViewById(R.id.swUpdates);
         swCrashReports = view.findViewById(R.id.swCrashReports);
         swDebug = view.findViewById(R.id.swDebug);
@@ -174,15 +172,6 @@ public class FragmentOptionsMisc extends FragmentBase implements SharedPreferenc
             }
         });
 
-        swPreferIp4.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {
-            @Override
-            public void onCheckedChanged(CompoundButton compoundButton, boolean checked) {
-                prefs.edit().putBoolean("prefer_ip4", checked).apply();
-                System.setProperty("java.net.preferIPv4Stack", Boolean.toString(checked));
-                ServiceSynchronize.reload(getContext(), "prefer_ip4=" + checked);
-            }
-        });
-
         swUpdates.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {
             @Override
             public void onCheckedChanged(CompoundButton compoundButton, boolean checked) {
@@ -321,7 +310,6 @@ public class FragmentOptionsMisc extends FragmentBase implements SharedPreferenc
         swDoubleBack.setChecked(prefs.getBoolean("double_back", true));
         swEnglish.setChecked(prefs.getBoolean("english", false));
         swWatchdog.setChecked(prefs.getBoolean("watchdog", true));
-        swPreferIp4.setChecked(prefs.getBoolean("prefer_ip4", false));
         swUpdates.setChecked(prefs.getBoolean("updates", true));
         swUpdates.setVisibility(Helper.isPlayStoreInstall(getContext()) ? View.GONE : View.VISIBLE);
         swCrashReports.setChecked(prefs.getBoolean("crash_reports", false));
diff --git a/app/src/main/java/eu/faircode/email/FragmentQuickSetup.java b/app/src/main/java/eu/faircode/email/FragmentQuickSetup.java
index d8597c8732..185ef1e063 100644
--- a/app/src/main/java/eu/faircode/email/FragmentQuickSetup.java
+++ b/app/src/main/java/eu/faircode/email/FragmentQuickSetup.java
@@ -243,7 +243,7 @@ public class FragmentQuickSetup extends FragmentBase {
                     Session isession = Session.getInstance(props, null);
                     isession.setDebug(true);
                     try (IMAPStore istore = (IMAPStore) isession.getStore(provider.imap_starttls ? "imap" : "imaps")) {
-                        istore.connect(provider.imap_host, provider.imap_port, user, password);
+                        ConnectionHelper.connect(context, isession, istore, provider.imap_host, provider.imap_port, user, password);
 
                         boolean inbox = false;
                         boolean drafts = false;
@@ -307,7 +307,7 @@ public class FragmentQuickSetup extends FragmentBase {
                     Session isession = Session.getInstance(props, null);
                     isession.setDebug(true);
                     try (Transport itransport = isession.getTransport(provider.smtp_starttls ? "smtp" : "smtps")) {
-                        itransport.connect(provider.smtp_host, provider.smtp_port, user, password);
+                        ConnectionHelper.connect(context, isession, itransport, provider.smtp_host, provider.smtp_port, user, password);
                     }
                 }
 
diff --git a/app/src/main/java/eu/faircode/email/MessageHelper.java b/app/src/main/java/eu/faircode/email/MessageHelper.java
index 6b3480f832..fa87fcfd6e 100644
--- a/app/src/main/java/eu/faircode/email/MessageHelper.java
+++ b/app/src/main/java/eu/faircode/email/MessageHelper.java
@@ -20,13 +20,10 @@ package eu.faircode.email;
 */
 
 import android.content.Context;
-import android.content.SharedPreferences;
 import android.net.MailTo;
 import android.text.TextUtils;
 import android.webkit.MimeTypeMap;
 
-import androidx.preference.PreferenceManager;
-
 import com.sun.mail.util.FolderClosedIOException;
 import com.sun.mail.util.MessageRemovedIOException;
 
@@ -102,12 +99,6 @@ public class MessageHelper {
         // https://docs.oracle.com/javaee/6/api/javax/mail/internet/MimeMultipart.html
         System.setProperty("mail.mime.multipart.ignoremissingboundaryparameter", "true"); // javax.mail.internet.ParseException: In parameter list
         System.setProperty("mail.mime.multipart.ignoreexistingboundaryparameter", "true");
-
-        // https://docs.oracle.com/javase/7/docs/api/java/net/doc-files/net-properties.html
-        SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(context);
-        boolean prefer_ip4 = prefs.getBoolean("prefer_ip4", false);
-        Log.i("Prefer ip4=" + prefer_ip4);
-        System.setProperty("java.net.preferIPv4Stack", Boolean.toString(prefer_ip4));
     }
 
     static Properties getSessionProperties(String realm, boolean insecure) {
diff --git a/app/src/main/java/eu/faircode/email/ServiceSend.java b/app/src/main/java/eu/faircode/email/ServiceSend.java
index 2fb0e2df5f..bfc70f7d86 100644
--- a/app/src/main/java/eu/faircode/email/ServiceSend.java
+++ b/app/src/main/java/eu/faircode/email/ServiceSend.java
@@ -367,7 +367,7 @@ public class ServiceSend extends ServiceBase {
         try (Transport itransport = isession.getTransport(protocol)) {
             // Connect transport
             db.identity().setIdentityState(ident.id, "connecting");
-            itransport.connect(ident.host, ident.port, ident.user, ident.password);
+            ConnectionHelper.connect(this, isession, itransport, ident);
             db.identity().setIdentityState(ident.id, "connected");
 
             // Send message
diff --git a/app/src/main/java/eu/faircode/email/ServiceSynchronize.java b/app/src/main/java/eu/faircode/email/ServiceSynchronize.java
index e6e3b0d6f0..d165655990 100644
--- a/app/src/main/java/eu/faircode/email/ServiceSynchronize.java
+++ b/app/src/main/java/eu/faircode/email/ServiceSynchronize.java
@@ -730,7 +730,7 @@ public class ServiceSynchronize extends ServiceBase {
                     db.account().setAccountState(account.id, "connecting");
 
                     try {
-                        ConnectionHelper.connect(this, istore, account);
+                        ConnectionHelper.connect(this, isession, istore, account);
                     } catch (Throwable ex) {
                         if (ex instanceof AuthenticationFailedException) {
                             NotificationManager nm = (NotificationManager) getSystemService(Context.NOTIFICATION_SERVICE);
diff --git a/app/src/main/res/layout/fragment_options_misc.xml b/app/src/main/res/layout/fragment_options_misc.xml
index e8580b0256..296afd2506 100644
--- a/app/src/main/res/layout/fragment_options_misc.xml
+++ b/app/src/main/res/layout/fragment_options_misc.xml
@@ -158,29 +158,6 @@
                 app:layout_constraintTop_toBottomOf="@id/tvEnglishHint"
                 app:switchPadding="12dp" />
 
-            <androidx.appcompat.widget.SwitchCompat
-                android:id="@+id/swPreferIp4"
-                android:layout_width="0dp"
-                android:layout_height="wrap_content"
-                android:layout_marginTop="12dp"
-                android:text="@string/title_advanced_prefer_ip4"
-                app:layout_constraintEnd_toEndOf="parent"
-                app:layout_constraintStart_toStartOf="parent"
-                app:layout_constraintTop_toBottomOf="@id/swWatchdog"
-                app:switchPadding="12dp" />
-
-            <TextView
-                android:id="@+id/tvPreferIp4Hint"
-                android:layout_width="0dp"
-                android:layout_height="wrap_content"
-                android:layout_marginEnd="48dp"
-                android:text="@string/title_advanced_prefer_ip4_hint"
-                android:textAppearance="@style/TextAppearance.AppCompat.Small"
-                android:textStyle="italic"
-                app:layout_constraintEnd_toEndOf="parent"
-                app:layout_constraintStart_toStartOf="parent"
-                app:layout_constraintTop_toBottomOf="@id/swPreferIp4" />
-
             <androidx.appcompat.widget.SwitchCompat
                 android:id="@+id/swUpdates"
                 android:layout_width="0dp"
@@ -190,7 +167,7 @@
                 android:text="@string/title_advanced_updates"
                 app:layout_constraintEnd_toEndOf="parent"
                 app:layout_constraintStart_toStartOf="parent"
-                app:layout_constraintTop_toBottomOf="@id/tvPreferIp4Hint"
+                app:layout_constraintTop_toBottomOf="@id/swWatchdog"
                 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 ff134f5105..78b6a935f3 100644
--- a/app/src/main/res/values/strings.xml
+++ b/app/src/main/res/values/strings.xml
@@ -260,7 +260,6 @@
     <string name="title_advanced_double_back">Double \'back\' to exit</string>
     <string name="title_advanced_english">Force English language</string>
     <string name="title_advanced_watchdog">Periodically check if FairEmail is still active</string>
-    <string name="title_advanced_prefer_ip4">Prefer IPv4 addresses</string>
     <string name="title_advanced_updates">Check for updates</string>
     <string name="title_advanced_crash_reports">Send error reports</string>
     <string name="title_advanced_debug">Debug mode</string>
@@ -301,7 +300,6 @@
     <string name="title_advanced_badge_hint">Only available on supported launchers</string>
     <string name="title_advanced_subscribed_only_hint">Enabling this will delete all local folders without subscription</string>
     <string name="title_advanced_english_hint">This will restart the app</string>
-    <string name="title_advanced_prefer_ip4_hint">Enable this only if IPv6 connectivity does not work properly</string>
     <string name="title_advanced_debug_hint">Enable extra logging and show debug information at various places</string>
     <string name="title_advanced_cleanup_hint">This will delete all temporary files</string>