diff --git a/app/src/main/java/eu/faircode/email/AdapterMessage.java b/app/src/main/java/eu/faircode/email/AdapterMessage.java
index 0a0d6e8fbb..56db5afe4e 100644
--- a/app/src/main/java/eu/faircode/email/AdapterMessage.java
+++ b/app/src/main/java/eu/faircode/email/AdapterMessage.java
@@ -257,6 +257,7 @@ public class AdapterMessage extends RecyclerView.Adapter<AdapterMessage.ViewHold
     private boolean avatars;
     private boolean color_stripe;
     private boolean check_authentication;
+    private boolean check_tls;
     private boolean check_reply_domain;
     private boolean check_mx;
     private boolean check_blocklist;
@@ -1207,12 +1208,11 @@ public class AdapterMessage extends RecyclerView.Adapter<AdapterMessage.ViewHold
                         !Boolean.FALSE.equals(message.dmarc))
                     auths = 3;
 
-                if (BuildConfig.DEBUG && auths > 1 && !Boolean.TRUE.equals(message.tls))
-                    auths--;
+                boolean verified = (auths == 3 && (!check_tls || Boolean.TRUE.equals(message.tls)));
 
                 ibAuth.setImageLevel(auths + 1);
                 ibAuth.setImageTintList(ColorStateList.valueOf(
-                        auths < 3 ? colorControlNormal : colorVerified));
+                        verified ? colorVerified : colorControlNormal));
                 ibAuth.setVisibility(auths > 0 ? View.VISIBLE : View.GONE);
             } else
                 ibAuth.setVisibility(View.GONE);
@@ -6162,6 +6162,7 @@ public class AdapterMessage extends RecyclerView.Adapter<AdapterMessage.ViewHold
         this.avatars = (contacts && avatars) || (gravatars || favicons || generated);
         this.color_stripe = prefs.getBoolean("color_stripe", true);
         this.check_authentication = prefs.getBoolean("check_authentication", true);
+        this.check_tls = prefs.getBoolean("check_tls", true);
         this.check_reply_domain = prefs.getBoolean("check_reply_domain", true);
         this.check_mx = prefs.getBoolean("check_mx", false);
         this.check_blocklist = prefs.getBoolean("check_blocklist", false);
diff --git a/app/src/main/java/eu/faircode/email/FragmentOptions.java b/app/src/main/java/eu/faircode/email/FragmentOptions.java
index add31b3d3f..617b29ae5b 100644
--- a/app/src/main/java/eu/faircode/email/FragmentOptions.java
+++ b/app/src/main/java/eu/faircode/email/FragmentOptions.java
@@ -123,7 +123,7 @@ public class FragmentOptions extends FragmentBase {
     static String[] OPTIONS_RESTART = new String[]{
             "first", "app_support", "notify_archive", "message_swipe", "message_select", "folder_actions", "folder_sync",
             "subscriptions",
-            "check_authentication", "check_reply_domain", "check_mx", "check_blocklist",
+            "check_authentication", "check_tls", "check_reply_domain", "check_mx", "check_blocklist",
             "send_pending",
             "startup", "cards", "beige", "tabular_card_bg", "shadow_unread", "shadow_highlight",
             "portrait2", "portrait2c", "portrait_min_size", "landscape", "landscape_min_size",
diff --git a/app/src/main/java/eu/faircode/email/FragmentOptionsSynchronize.java b/app/src/main/java/eu/faircode/email/FragmentOptionsSynchronize.java
index a949ff9330..af26da3db8 100644
--- a/app/src/main/java/eu/faircode/email/FragmentOptionsSynchronize.java
+++ b/app/src/main/java/eu/faircode/email/FragmentOptionsSynchronize.java
@@ -91,6 +91,7 @@ public class FragmentOptionsSynchronize extends FragmentBase implements SharedPr
     private SwitchCompat swTuneKeepAlive;
 
     private SwitchCompat swCheckAuthentication;
+    private SwitchCompat swCheckTls;
     private SwitchCompat swCheckReply;
     private SwitchCompat swCheckMx;
     private SwitchCompat swCheckBlocklist;
@@ -108,7 +109,7 @@ public class FragmentOptionsSynchronize extends FragmentBase implements SharedPr
             "sync_nodate", "sync_unseen", "sync_flagged", "delete_unseen", "sync_kept",
             "gmail_thread_id", "subject_threading",
             "sync_folders", "sync_folders_poll", "sync_shared_folders", "subscriptions",
-            "check_authentication", "check_reply_domain", "check_mx", "check_blocklist", "use_blocklist",
+            "check_authentication", "check_tls", "check_reply_domain", "check_mx", "check_blocklist", "use_blocklist",
             "tune_keep_alive"
     };
 
@@ -161,6 +162,7 @@ public class FragmentOptionsSynchronize extends FragmentBase implements SharedPr
         swTuneKeepAlive = view.findViewById(R.id.swTuneKeepAlive);
 
         swCheckAuthentication = view.findViewById(R.id.swCheckAuthentication);
+        swCheckTls = view.findViewById(R.id.swCheckTls);
         swCheckReply = view.findViewById(R.id.swCheckReply);
         swCheckMx = view.findViewById(R.id.swCheckMx);
         swCheckBlocklist = view.findViewById(R.id.swCheckBlocklist);
@@ -382,6 +384,14 @@ public class FragmentOptionsSynchronize extends FragmentBase implements SharedPr
             @Override
             public void onCheckedChanged(CompoundButton buttonView, boolean checked) {
                 prefs.edit().putBoolean("check_authentication", checked).apply();
+                swCheckTls.setEnabled(checked);
+            }
+        });
+
+        swCheckTls.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {
+            @Override
+            public void onCheckedChanged(CompoundButton buttonView, boolean checked) {
+                prefs.edit().putBoolean("check_tls", checked).apply();
             }
         });
 
@@ -518,6 +528,8 @@ public class FragmentOptionsSynchronize extends FragmentBase implements SharedPr
         swSubscriptions.setChecked(prefs.getBoolean("subscriptions", false));
         swTuneKeepAlive.setChecked(prefs.getBoolean("tune_keep_alive", true));
         swCheckAuthentication.setChecked(prefs.getBoolean("check_authentication", true));
+        swCheckTls.setChecked(prefs.getBoolean("check_tls", false));
+        swCheckTls.setEnabled(swCheckAuthentication.isChecked());
         swCheckReply.setChecked(prefs.getBoolean("check_reply_domain", true));
         swCheckMx.setChecked(prefs.getBoolean("check_mx", false));
         swCheckBlocklist.setChecked(prefs.getBoolean("check_blocklist", false));
diff --git a/app/src/main/res/layout/fragment_options_synchronize.xml b/app/src/main/res/layout/fragment_options_synchronize.xml
index 10c7e6e650..2b682294f6 100644
--- a/app/src/main/res/layout/fragment_options_synchronize.xml
+++ b/app/src/main/res/layout/fragment_options_synchronize.xml
@@ -745,6 +745,18 @@
                     app:layout_constraintStart_toStartOf="parent"
                     app:layout_constraintTop_toBottomOf="@id/swCheckAuthentication" />
 
+                <androidx.appcompat.widget.SwitchCompat
+                    android:id="@+id/swCheckTls"
+                    android:layout_width="0dp"
+                    android:layout_height="wrap_content"
+                    android:layout_marginStart="12dp"
+                    android:layout_marginTop="12dp"
+                    android:text="@string/title_advanced_check_tls"
+                    app:layout_constraintEnd_toEndOf="parent"
+                    app:layout_constraintStart_toStartOf="parent"
+                    app:layout_constraintTop_toBottomOf="@id/tvCheckAuthenticationHint"
+                    app:switchPadding="12dp" />
+
                 <androidx.appcompat.widget.SwitchCompat
                     android:id="@+id/swCheckReply"
                     android:layout_width="0dp"
@@ -754,7 +766,7 @@
                     android:text="@string/title_advanced_check_reply_domain"
                     app:layout_constraintEnd_toEndOf="parent"
                     app:layout_constraintStart_toStartOf="parent"
-                    app:layout_constraintTop_toBottomOf="@id/tvCheckAuthenticationHint"
+                    app:layout_constraintTop_toBottomOf="@id/swCheckTls"
                     app:switchPadding="12dp" />
 
                 <eu.faircode.email.FixedTextView
diff --git a/app/src/main/res/values/strings.xml b/app/src/main/res/values/strings.xml
index 0c22085855..bfc9550a7c 100644
--- a/app/src/main/res/values/strings.xml
+++ b/app/src/main/res/values/strings.xml
@@ -357,6 +357,7 @@
     <string name="title_advanced_sync_shared_folders">Synchronize shared folder lists</string>
     <string name="title_advanced_subscriptions">Manage folder subscriptions</string>
     <string name="title_advanced_check_authentication">Check message authentication</string>
+    <string name="title_advanced_check_tls">Check transport layer security (TLS)</string>
     <string name="title_advanced_check_reply_domain">Check reply address on synchronizing messages</string>
     <string name="title_advanced_check_mx">Check sender email addresses on synchronizing messages</string>
     <string name="title_advanced_check_blocklist">Check if the sender\'s domain name is on a spam block list</string>