Prevent using background service on Android O+

app/src/main/java/eu/faircode/email/ActivitySetup.java

@@ -958,6 +958,10 @@ public class ActivitySetup extends ActivityBase implements FragmentManager.OnBac
                         if ("alert_once".equals(key) && !Log.isXiaomi())
                             continue;
 
+                        if ("background_service".equals(key) &&
+                                Build.VERSION.SDK_INT >= Build.VERSION_CODES.O)
+                            continue;
+
                         if (key != null && key.startsWith("widget."))
                             continue;
 

app/src/main/java/eu/faircode/email/ApplicationEx.java

@@ -351,6 +351,9 @@ public class ApplicationEx extends Application implements SharedPreferences.OnSh
                 editor.putBoolean("beige", false);
         }
 
+        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O)
+            editor.remove("background_service");
+
         if (version < BuildConfig.VERSION_CODE)
             editor.putInt("previous_version", version);
         editor.putInt("version", BuildConfig.VERSION_CODE);

app/src/main/java/eu/faircode/email/ServiceSynchronize.java

@@ -2256,7 +2256,7 @@ public class ServiceSynchronize extends ServiceBase implements SharedPreferences
     private static void start(Context context, Intent intent) {
         SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(context);
         boolean background_service = prefs.getBoolean("background_service", false);
-        if (background_service && Build.VERSION.SDK_INT < Build.VERSION_CODES.O)
+        if (background_service)
             context.startService(intent);
         else
             ContextCompat.startForegroundService(context, intent);