diff --git a/app/src/main/java/eu/faircode/email/AdapterMessage.java b/app/src/main/java/eu/faircode/email/AdapterMessage.java
index 4576b56ffa..4515f4a90c 100644
--- a/app/src/main/java/eu/faircode/email/AdapterMessage.java
+++ b/app/src/main/java/eu/faircode/email/AdapterMessage.java
@@ -224,6 +224,7 @@ public class AdapterMessage extends RecyclerView.Adapter<AdapterMessage.ViewHold
 
     private boolean date;
     private boolean threading;
+    private boolean threading_unread;
     private boolean avatars;
     private boolean color_stripe;
     private boolean name_email;
@@ -1043,8 +1044,10 @@ public class AdapterMessage extends RecyclerView.Adapter<AdapterMessage.ViewHold
                 tvCount.setVisibility(threading ? View.VISIBLE : View.GONE);
                 ivThread.setVisibility(View.VISIBLE);
 
-                if (BuildConfig.DEBUG)
-                    tvCount.setText(NF.format(message.visible_unseen) + "/" + NF.format(message.visible));
+                if (threading_unread)
+                    tvCount.setText(context.getString(R.string.title_of,
+                            NF.format(message.visible_unseen),
+                            NF.format(message.visible)));
                 else
                     tvCount.setText(NF.format(message.visible));
 
@@ -4783,6 +4786,7 @@ public class AdapterMessage extends RecyclerView.Adapter<AdapterMessage.ViewHold
 
         this.date = prefs.getBoolean("date", true);
         this.threading = prefs.getBoolean("threading", true);
+        this.threading_unread = threading && prefs.getBoolean("threading_unread", false);
         this.avatars = (contacts && avatars) || generated;
         this.color_stripe = prefs.getBoolean("color_stripe", true);
         this.name_email = prefs.getBoolean("name_email", false);
diff --git a/app/src/main/java/eu/faircode/email/FragmentOptions.java b/app/src/main/java/eu/faircode/email/FragmentOptions.java
index defac2c9ec..148911fa07 100644
--- a/app/src/main/java/eu/faircode/email/FragmentOptions.java
+++ b/app/src/main/java/eu/faircode/email/FragmentOptions.java
@@ -54,7 +54,7 @@ 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",
-            "landscape", "landscape3", "startup", "cards", "indentation", "date", "threading",
+            "landscape", "landscape3", "startup", "cards", "indentation", "date", "threading", "threading_unread",
             "highlight_unread", "color_stripe",
             "avatars", "gravatars", "generated_icons", "identicons", "circular", "saturation", "brightness", "threshold",
             "name_email", "prefer_contact", "distinguish_contacts", "show_recipients", "authentication",
diff --git a/app/src/main/java/eu/faircode/email/FragmentOptionsDisplay.java b/app/src/main/java/eu/faircode/email/FragmentOptionsDisplay.java
index 7c8ec5f6ea..de2ee3c8f2 100644
--- a/app/src/main/java/eu/faircode/email/FragmentOptionsDisplay.java
+++ b/app/src/main/java/eu/faircode/email/FragmentOptionsDisplay.java
@@ -64,6 +64,7 @@ public class FragmentOptionsDisplay extends FragmentBase implements SharedPrefer
     private SwitchCompat swLandscape3;
 
     private SwitchCompat swThreading;
+    private SwitchCompat swThreadingUnread;
     private SwitchCompat swIndentation;
     private SwitchCompat swSeekbar;
     private SwitchCompat swActionbar;
@@ -118,7 +119,7 @@ public class FragmentOptionsDisplay extends FragmentBase implements SharedPrefer
 
     private final static String[] RESET_OPTIONS = new String[]{
             "theme", "startup", "cards", "date", "navbar_colorize", "landscape", "landscape3",
-            "threading", "indentation", "seekbar", "actionbar", "actionbar_color",
+            "threading", "threading_unread", "indentation", "seekbar", "actionbar", "actionbar_color",
             "highlight_unread", "color_stripe",
             "avatars", "gravatars", "generated_icons", "identicons", "circular", "saturation", "brightness", "threshold",
             "name_email", "prefer_contact", "distinguish_contacts", "show_recipients",
@@ -150,6 +151,7 @@ public class FragmentOptionsDisplay extends FragmentBase implements SharedPrefer
         swLandscape3 = view.findViewById(R.id.swLandscape3);
 
         swThreading = view.findViewById(R.id.swThreading);
+        swThreadingUnread = view.findViewById(R.id.swThreadingUnread);
         swIndentation = view.findViewById(R.id.swIndentation);
         swSeekbar = view.findViewById(R.id.swSeekbar);
         swActionbar = view.findViewById(R.id.swActionbar);
@@ -268,10 +270,18 @@ public class FragmentOptionsDisplay extends FragmentBase implements SharedPrefer
             @Override
             public void onCheckedChanged(CompoundButton compoundButton, boolean checked) {
                 prefs.edit().putBoolean("threading", checked).apply();
+                swThreadingUnread.setEnabled(checked);
                 WidgetUnified.updateData(getContext());
             }
         });
 
+        swThreadingUnread.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {
+            @Override
+            public void onCheckedChanged(CompoundButton compoundButton, boolean checked) {
+                prefs.edit().putBoolean("threading_unread", checked).apply();
+            }
+        });
+
         swIndentation.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {
             @Override
             public void onCheckedChanged(CompoundButton compoundButton, boolean checked) {
@@ -725,6 +735,8 @@ public class FragmentOptionsDisplay extends FragmentBase implements SharedPrefer
         swLandscape3.setEnabled(normal && swLandscape.isChecked());
 
         swThreading.setChecked(prefs.getBoolean("threading", true));
+        swThreadingUnread.setChecked(prefs.getBoolean("threading_unread", false));
+        swThreadingUnread.setEnabled(swThreading.isChecked());
         swIndentation.setChecked(prefs.getBoolean("indentation", false));
         swIndentation.setEnabled(swCards.isChecked());
         swSeekbar.setChecked(prefs.getBoolean("seekbar", false));
diff --git a/app/src/main/res/layout/fragment_options_display.xml b/app/src/main/res/layout/fragment_options_display.xml
index 275526e8ea..ec112e23c9 100644
--- a/app/src/main/res/layout/fragment_options_display.xml
+++ b/app/src/main/res/layout/fragment_options_display.xml
@@ -205,6 +205,17 @@
             app:layout_constraintStart_toStartOf="parent"
             app:layout_constraintTop_toBottomOf="@id/swThreading" />
 
+        <androidx.appcompat.widget.SwitchCompat
+            android:id="@+id/swThreadingUnread"
+            android:layout_width="0dp"
+            android:layout_height="wrap_content"
+            android:layout_marginTop="12dp"
+            android:text="@string/title_advanced_threading_unread"
+            app:layout_constraintEnd_toEndOf="parent"
+            app:layout_constraintStart_toStartOf="parent"
+            app:layout_constraintTop_toBottomOf="@id/tvThreadingHint"
+            app:switchPadding="12dp" />
+
         <androidx.appcompat.widget.SwitchCompat
             android:id="@+id/swIndentation"
             android:layout_width="0dp"
@@ -214,7 +225,7 @@
             android:text="@string/title_advanced_indentation"
             app:layout_constraintEnd_toEndOf="parent"
             app:layout_constraintStart_toStartOf="parent"
-            app:layout_constraintTop_toBottomOf="@id/tvThreadingHint"
+            app:layout_constraintTop_toBottomOf="@id/swThreadingUnread"
             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 6048075566..af9a2f0d59 100644
--- a/app/src/main/res/values/strings.xml
+++ b/app/src/main/res/values/strings.xml
@@ -99,6 +99,7 @@
     <string name="title_notification_failed">\'%1$s\' failed</string>
     <string name="title_notification_alert">\'%1$s\' server alert</string>
 
+    <string name="title_of">%1$s/%2$s</string>
     <string name="title_name_count">%1$s (%2$s)</string>
     <string name="title_name_plus">%1$s +%2$d</string>
     <string name="title_from_to">%1$s ➤ %2$s</string>
@@ -316,6 +317,7 @@
     <string name="title_advanced_cards">Use card style instead of tabular style</string>
     <string name="title_advanced_date_header">Group by date</string>
     <string name="title_advanced_threading">Conversation threading</string>
+    <string name="title_advanced_threading_unread">Show number of unread messages in conversations</string>
     <string name="title_advanced_indentation">Left/right indent received/sent messages in conversations</string>
     <string name="title_advanced_highlight_unread">Highlight unread messages</string>
     <string name="title_advanced_highlight_subject">Highlight subject</string>