diff --git a/app/src/main/java/eu/faircode/email/DaoMessage.java b/app/src/main/java/eu/faircode/email/DaoMessage.java
index ac91072883..1aeef4f228 100644
--- a/app/src/main/java/eu/faircode/email/DaoMessage.java
+++ b/app/src/main/java/eu/faircode/email/DaoMessage.java
@@ -209,9 +209,6 @@ public interface DaoMessage {
     @Query("UPDATE message SET avatar = :avatar WHERE id = :id")
     int setMessageAvatar(long id, String avatar);
 
-    @Query("UPDATE message SET avatar = NULL")
-    void clearMessageAvatars();
-
     @Query("DELETE FROM message WHERE id = :id")
     int deleteMessage(long id);
 
diff --git a/app/src/main/java/eu/faircode/email/FragmentOptions.java b/app/src/main/java/eu/faircode/email/FragmentOptions.java
index 05514e278b..baff3aff1f 100644
--- a/app/src/main/java/eu/faircode/email/FragmentOptions.java
+++ b/app/src/main/java/eu/faircode/email/FragmentOptions.java
@@ -22,7 +22,6 @@ package eu.faircode.email;
 import android.content.SharedPreferences;
 import android.os.Bundle;
 import android.preference.PreferenceManager;
-import android.util.Log;
 import android.view.LayoutInflater;
 import android.view.View;
 import android.view.ViewGroup;
@@ -36,6 +35,7 @@ public class FragmentOptions extends FragmentEx {
     private CheckBox cbCompressImap;
     private CheckBox cbAvatars;
     private CheckBox cbLight;
+    private CheckBox cbIpV4;
     private CheckBox cbDebug;
 
     @Override
@@ -49,6 +49,7 @@ public class FragmentOptions extends FragmentEx {
         cbCompressImap = view.findViewById(R.id.cbCompressImap);
         cbAvatars = view.findViewById(R.id.cbAvatars);
         cbLight = view.findViewById(R.id.cbLight);
+        cbIpV4 = view.findViewById(R.id.cbIpV4);
         cbDebug = view.findViewById(R.id.cbDebug);
 
         // Wire controls
@@ -60,6 +61,7 @@ public class FragmentOptions extends FragmentEx {
             @Override
             public void onCheckedChanged(CompoundButton compoundButton, boolean checked) {
                 prefs.edit().putBoolean("compress", checked).apply();
+                ServiceSynchronize.reload(getContext(), "compress=" + checked);
             }
         });
 
@@ -68,14 +70,6 @@ public class FragmentOptions extends FragmentEx {
             @Override
             public void onCheckedChanged(CompoundButton compoundButton, boolean checked) {
                 prefs.edit().putBoolean("avatars", checked).apply();
-                if (!checked)
-                    new Thread(new Runnable() {
-                        @Override
-                        public void run() {
-                            Log.i(Helper.TAG, "Clearing avatars");
-                            DB.getInstance(getContext()).message().clearMessageAvatars();
-                        }
-                    }).start();
             }
         });
 
@@ -87,11 +81,21 @@ public class FragmentOptions extends FragmentEx {
             }
         });
 
+        cbIpV4.setChecked(prefs.getBoolean("ipv4", false));
+        cbIpV4.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {
+            @Override
+            public void onCheckedChanged(CompoundButton compoundButton, boolean checked) {
+                prefs.edit().putBoolean("ipv4", checked).apply();
+                ServiceSynchronize.reload(getContext(), "IPv4=" + checked);
+            }
+        });
+
         cbDebug.setChecked(prefs.getBoolean("debug", false));
         cbDebug.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {
             @Override
             public void onCheckedChanged(CompoundButton compoundButton, boolean checked) {
                 prefs.edit().putBoolean("debug", checked).apply();
+                ServiceSynchronize.reload(getContext(), "debug=" + checked);
             }
         });
 
diff --git a/app/src/main/java/eu/faircode/email/MessageHelper.java b/app/src/main/java/eu/faircode/email/MessageHelper.java
index eaff9b101b..579106ef07 100644
--- a/app/src/main/java/eu/faircode/email/MessageHelper.java
+++ b/app/src/main/java/eu/faircode/email/MessageHelper.java
@@ -140,7 +140,10 @@ public class MessageHelper {
         System.setProperty("mail.mime.multipart.ignoremissingboundaryparameter", "true"); // javax.mail.internet.ParseException: In parameter list
         System.setProperty("mail.mime.multipart.ignoreexistingboundaryparameter", "true");
 
-        //System.setProperty("java.net.preferIPv4Stack", "true");
+        if (prefs.getBoolean("ipv4", false)) {
+            Log.i(Helper.TAG, "Prefering IPv4");
+            System.setProperty("java.net.preferIPv4Stack", "true");
+        }
 
         // https://javaee.github.io/javamail/OAuth2
         Log.i(Helper.TAG, "Auth type=" + auth_type);
diff --git a/app/src/main/res/layout/fragment_options.xml b/app/src/main/res/layout/fragment_options.xml
index 8f4ce340df..bf9b49d034 100644
--- a/app/src/main/res/layout/fragment_options.xml
+++ b/app/src/main/res/layout/fragment_options.xml
@@ -41,6 +41,16 @@
             app:layout_constraintStart_toStartOf="parent"
             app:layout_constraintTop_toBottomOf="@id/cbAvatars" />
 
+        <CheckBox
+            android:id="@+id/cbIpV4"
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content"
+            android:layout_marginStart="12dp"
+            android:layout_marginTop="12dp"
+            android:text="@string/title_advanced_ipv4"
+            app:layout_constraintStart_toStartOf="parent"
+            app:layout_constraintTop_toBottomOf="@id/cbLight" />
+
         <CheckBox
             android:id="@+id/cbDebug"
             android:layout_width="wrap_content"
@@ -49,6 +59,6 @@
             android:layout_marginTop="12dp"
             android:text="@string/title_advanced_debug"
             app:layout_constraintStart_toStartOf="parent"
-            app:layout_constraintTop_toBottomOf="@id/cbLight" />
+            app:layout_constraintTop_toBottomOf="@id/cbIpV4" />
     </androidx.constraintlayout.widget.ConstraintLayout>
 </ScrollView>
\ No newline at end of file
diff --git a/app/src/main/res/values/strings.xml b/app/src/main/res/values/strings.xml
index 963c7c4526..4fbc7215d7 100644
--- a/app/src/main/res/values/strings.xml
+++ b/app/src/main/res/values/strings.xml
@@ -79,6 +79,7 @@
     <string name="title_advanced_compress_imap">Compress IMAP data</string>
     <string name="title_advanced_avatars">Show contact photos</string>
     <string name="title_advanced_light">Use notification light</string>
+    <string name="title_advanced_ipv4">Prefer IPv4 connections</string>
     <string name="title_advanced_debug">Debug</string>
 
     <string name="title_select">Select &#8230;</string>