diff --git a/android_app/app/build.gradle b/android_app/app/build.gradle
index 5f6729c6..dd4e5611 100644
--- a/android_app/app/build.gradle
+++ b/android_app/app/build.gradle
@@ -6,7 +6,7 @@ android {
     defaultConfig {
         applicationId "com.health.openscale"
         testApplicationId "com.health.openscale.test"
-        minSdkVersion 21
+        minSdkVersion 23
         targetSdkVersion 31
         versionCode 58
         versionName "2.4.3"
diff --git a/android_app/app/src/main/java/com/health/openscale/core/alarm/AlarmBackupHandler.java b/android_app/app/src/main/java/com/health/openscale/core/alarm/AlarmBackupHandler.java
index d2880147..41aa5724 100644
--- a/android_app/app/src/main/java/com/health/openscale/core/alarm/AlarmBackupHandler.java
+++ b/android_app/app/src/main/java/com/health/openscale/core/alarm/AlarmBackupHandler.java
@@ -75,7 +75,7 @@ public class AlarmBackupHandler
         Intent alarmIntent = new Intent(context, ReminderBootReceiver.class);
         alarmIntent.putExtra(INTENT_EXTRA_BACKUP_ALARM, true);
 
-        return PendingIntent.getBroadcast(context, ALARM_NOTIFICATION_ID, alarmIntent, PendingIntent.FLAG_UPDATE_CURRENT);
+        return PendingIntent.getBroadcast(context, ALARM_NOTIFICATION_ID, alarmIntent, PendingIntent.FLAG_UPDATE_CURRENT | PendingIntent.FLAG_IMMUTABLE);
     }
 
     public void disableAlarm(Context context) {
diff --git a/android_app/app/src/main/java/com/health/openscale/core/alarm/AlarmHandler.java b/android_app/app/src/main/java/com/health/openscale/core/alarm/AlarmHandler.java
index 049ac5a6..68ee9777 100644
--- a/android_app/app/src/main/java/com/health/openscale/core/alarm/AlarmHandler.java
+++ b/android_app/app/src/main/java/com/health/openscale/core/alarm/AlarmHandler.java
@@ -15,6 +15,8 @@
 */
 package com.health.openscale.core.alarm;
 
+import static android.content.Context.NOTIFICATION_SERVICE;
+
 import android.app.AlarmManager;
 import android.app.Notification;
 import android.app.NotificationChannel;
@@ -25,6 +27,8 @@ import android.content.Intent;
 import android.os.Build;
 import android.service.notification.StatusBarNotification;
 
+import androidx.core.app.NotificationCompat;
+
 import com.health.openscale.R;
 import com.health.openscale.core.datatypes.ScaleMeasurement;
 import com.health.openscale.gui.MainActivity;
@@ -34,11 +38,8 @@ import java.util.LinkedList;
 import java.util.List;
 import java.util.Set;
 
-import androidx.core.app.NotificationCompat;
 import timber.log.Timber;
 
-import static android.content.Context.NOTIFICATION_SERVICE;
-
 public class AlarmHandler
 {
     public static final String INTENT_EXTRA_ALARM = "alarmIntent";
@@ -116,7 +117,7 @@ public class AlarmHandler
         Intent alarmIntent = new Intent(context, ReminderBootReceiver.class);
         alarmIntent.putExtra(INTENT_EXTRA_ALARM, true);
 
-        return PendingIntent.getBroadcast(context, dayOfWeek, alarmIntent, PendingIntent.FLAG_UPDATE_CURRENT);
+        return PendingIntent.getBroadcast(context, dayOfWeek, alarmIntent, PendingIntent.FLAG_UPDATE_CURRENT | PendingIntent.FLAG_IMMUTABLE);
     }
 
     public void disableAllAlarms(Context context)
@@ -156,7 +157,7 @@ public class AlarmHandler
         Intent notifyIntent = new Intent(context, MainActivity.class);
 
         PendingIntent notifyPendingIntent =
-                PendingIntent.getActivity(context, 0, notifyIntent, PendingIntent.FLAG_UPDATE_CURRENT);
+                PendingIntent.getActivity(context, 0, notifyIntent, PendingIntent.FLAG_UPDATE_CURRENT | PendingIntent.FLAG_IMMUTABLE);
 
         NotificationCompat.Builder mBuilder = new NotificationCompat.Builder(context, "openScale_notify");
 
diff --git a/android_app/app/src/main/java/com/health/openscale/gui/widget/WidgetProvider.java b/android_app/app/src/main/java/com/health/openscale/gui/widget/WidgetProvider.java
index 3fc7cb2e..51ac866b 100644
--- a/android_app/app/src/main/java/com/health/openscale/gui/widget/WidgetProvider.java
+++ b/android_app/app/src/main/java/com/health/openscale/gui/widget/WidgetProvider.java
@@ -144,7 +144,7 @@ public class WidgetProvider extends AppWidgetProvider {
 
         // Start main activity when widget is clicked
         Intent intent = new Intent(context, MainActivity.class);
-        PendingIntent pendingIntent = PendingIntent.getActivity(context, 0, intent, 0);
+        PendingIntent pendingIntent = PendingIntent.getActivity(context, 0, intent, PendingIntent.FLAG_IMMUTABLE);
         views.setOnClickPendingIntent(R.id.widget_layout, pendingIntent);
 
         appWidgetManager.updateAppWidget(appWidgetId, views);