diff --git a/app/src/main/java/org/mercury_im/messenger/ClientStateHandler.java b/app/src/main/java/org/mercury_im/messenger/ClientStateHandler.java
new file mode 100644
index 0000000..7d4426c
--- /dev/null
+++ b/app/src/main/java/org/mercury_im/messenger/ClientStateHandler.java
@@ -0,0 +1,52 @@
+package org.mercury_im.messenger;
+
+import android.app.Activity;
+
+import org.mercury_im.messenger.util.AbstractActivityLifecycleCallbacks;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.concurrent.atomic.AtomicBoolean;
+import java.util.concurrent.atomic.AtomicInteger;
+
+/**
+ * Keep track of activities in "started" state.
+ * This will come in handy for things like XMPPs CSI.
+ *
+ * @see <a href="https://medium.com/@iamsadesh/android-how-to-detect-when-app-goes-background-foreground-fd5a4d331f8a>
+ *     How to detect when app goes foreground/background</a>
+ */
+public class ClientStateHandler extends AbstractActivityLifecycleCallbacks {
+
+    private AtomicInteger activityReferences = new AtomicInteger(0);
+    private AtomicBoolean isActivityChangingConfiguration = new AtomicBoolean(false);
+
+    private final List<ClientStateListener> listeners = new ArrayList<>();
+
+    @Override
+    public void onActivityStarted(Activity activity) {
+        if (activityReferences.incrementAndGet() == 1 && !isActivityChangingConfiguration.get()) {
+            for (ClientStateListener listener : listeners) {
+                listener.onClientInForeground();
+            }
+        }
+    }
+
+    @Override
+    public void onActivityStopped(Activity activity) {
+        isActivityChangingConfiguration.set(activity.isChangingConfigurations());
+        if (activityReferences.decrementAndGet() == 0 && !isActivityChangingConfiguration.get()) {
+            for (ClientStateListener listener : listeners) {
+                listener.onClientInBackground();
+            }
+        }
+    }
+
+    public void addClientStateListener(ClientStateListener listener) {
+        this.listeners.add(listener);
+    }
+
+    public void removeClientStateListener(ClientStateListener listener) {
+        this.listeners.remove(listener);
+    }
+}
diff --git a/app/src/main/java/org/mercury_im/messenger/MercuryImApplication.java b/app/src/main/java/org/mercury_im/messenger/MercuryImApplication.java
index 82c5af4..a27139d 100644
--- a/app/src/main/java/org/mercury_im/messenger/MercuryImApplication.java
+++ b/app/src/main/java/org/mercury_im/messenger/MercuryImApplication.java
@@ -1,11 +1,6 @@
 package org.mercury_im.messenger;
 
-import android.annotation.SuppressLint;
-import android.app.Activity;
 import android.app.Application;
-import android.app.NotificationChannel;
-import android.app.NotificationManager;
-import android.content.Context;
 import android.content.Intent;
 import android.os.Build;
 
@@ -13,10 +8,6 @@ import org.mercury_im.messenger.di.component.AppComponent;
 import org.mercury_im.messenger.di.component.DaggerAppComponent;
 import org.mercury_im.messenger.di.module.AppModule;
 import org.mercury_im.messenger.service.MercuryConnectionService;
-import org.mercury_im.messenger.util.AbstractActivityLifecycleCallbacks;
-
-import java.util.concurrent.atomic.AtomicBoolean;
-import java.util.concurrent.atomic.AtomicInteger;
 
 
 public class MercuryImApplication extends Application {
@@ -27,13 +18,8 @@ public class MercuryImApplication extends Application {
     }
 
     private static MercuryImApplication INSTANCE;
-    AppComponent appComponent;
-
-    // Keep track of activities in "started" state.
-    // This will come in handy for CSI
-    // see https://medium.com/@iamsadesh/android-how-to-detect-when-app-goes-background-foreground-fd5a4d331f8a
-    private AtomicInteger activityReferences = new AtomicInteger(0);
-    private AtomicBoolean isActivityChangingConfiguration = new AtomicBoolean(false);
+    private AppComponent appComponent;
+    private ClientStateHandler clientStateHandler = new ClientStateHandler();
 
     public static MercuryImApplication getApplication() {
         return INSTANCE;
@@ -42,29 +28,18 @@ public class MercuryImApplication extends Application {
 
     @Override
     public void onCreate() {
-
         super.onCreate();
-        registerActivityLifecycleCallbacks(lifecycleCallbacks);
-
         INSTANCE = this;
-
         appComponent = createAppComponent();
 
-        initializeNotificationChannels(this);
+        registerActivityLifecycleCallbacks(clientStateHandler);
+        Notifications.initializeNotificationChannels(this);
 
-        Intent serviceIntent = new Intent(getApplicationContext(), MercuryConnectionService.class);
-
-        serviceIntent.setAction(MercuryConnectionService.ACTION_START);
-        if (Build.VERSION.SDK_INT < 26) {
-            startService(serviceIntent);
-        } else {
-            startForegroundService(serviceIntent);
-        }
+        startForegroundService();
     }
 
     /**
      * Create the Dependency Injection graph.
-     * For testing, overwrite this method with custom modules.
      */
     public AppComponent createAppComponent() {
         AppComponent appComponent = DaggerAppComponent.builder()
@@ -76,58 +51,17 @@ public class MercuryImApplication extends Application {
         return appComponent;
     }
 
-    public void initializeNotificationChannels(Context context) {
-        // Only necessary on Android O and upwards.
-        if (Build.VERSION.SDK_INT < 26) {
-            return;
-        }
-
-        NotificationManager notificationManager =
-                (NotificationManager) context.getSystemService(Context.NOTIFICATION_SERVICE);
-
-        // Foreground notification channel
-        String fName = getResources().getString(R.string.channel_name_foreground);
-        String fDescription = getResources().getString(R.string.channel_description_foreground);
-
-        @SuppressLint("WrongConstant")
-        NotificationChannel foreground = new NotificationChannel(Notifications.NOTIFICATION_CHANNEL__FOREGROUND_SERVICE,
-                fName, NotificationManager.IMPORTANCE_MIN);
-        foreground.setDescription(fDescription);
-        foreground.setShowBadge(false);
-        notificationManager.createNotificationChannel(foreground);
-
-        // Incoming Messages notification channel
-        String mName = getResources().getString(R.string.channel_name_message);
-        String mDescription = getResources().getString(R.string.channel_description_message);
-
-        @SuppressLint("WrongConstant")
-        NotificationChannel messages = new NotificationChannel(Notifications.NOTIFICATION_CHANNEL__NEW_MESSAGE,
-                mName, NotificationManager.IMPORTANCE_DEFAULT);
-        messages.setDescription(mDescription);
-        notificationManager.createNotificationChannel(messages);
-    }
-
     public AppComponent getAppComponent() {
         return appComponent;
     }
 
-    private final AbstractActivityLifecycleCallbacks lifecycleCallbacks = new AbstractActivityLifecycleCallbacks() {
-
-        @Override
-        public void onActivityStarted(Activity activity) {
-            if (activityReferences.incrementAndGet() == 1 && !isActivityChangingConfiguration.get()) {
-                // App enters foreground
-                //connectionCenter.clientStateActive();
-            }
+    private void startForegroundService() {
+        Intent foregroundService = new Intent(getApplicationContext(), MercuryConnectionService.class);
+        foregroundService.setAction(MercuryConnectionService.ACTION_START);
+        if (Build.VERSION.SDK_INT < 26) {
+            startService(foregroundService);
+        } else {
+            startForegroundService(foregroundService);
         }
-
-        @Override
-        public void onActivityStopped(Activity activity) {
-            isActivityChangingConfiguration.set(activity.isChangingConfigurations());
-            if (activityReferences.decrementAndGet() == 0 && !isActivityChangingConfiguration.get()) {
-                // App enters background
-                //connectionCenter.clientStateInactive();
-            }
-        }
-    };
+    }
 }
diff --git a/app/src/main/java/org/mercury_im/messenger/Notifications.java b/app/src/main/java/org/mercury_im/messenger/Notifications.java
index 51f99ff..4d22b87 100644
--- a/app/src/main/java/org/mercury_im/messenger/Notifications.java
+++ b/app/src/main/java/org/mercury_im/messenger/Notifications.java
@@ -1,8 +1,12 @@
 package org.mercury_im.messenger;
 
+import android.annotation.TargetApi;
+import android.app.NotificationChannel;
+import android.app.NotificationManager;
 import android.app.PendingIntent;
 import android.content.Context;
 import android.content.Intent;
+import android.os.Build;
 
 import androidx.core.app.NotificationCompat;
 import androidx.core.app.NotificationManagerCompat;
@@ -18,7 +22,43 @@ public class Notifications {
     public static final String NOTIFICATION_CHANNEL__DEBUG = "debug";
 
     // Notification IDs
-    public static final int FOREGROUND_SERVICE_ID = 1; // must not be 0
+    public static final int FOREGROUND_SERVICE_ID = 1;
+
+    public static void initializeNotificationChannels(Context context) {
+        if (Build.VERSION.SDK_INT < 26) {
+            // No not call below code on lower API levels
+            return;
+        }
+        createForegroundNotificationChannel(context);
+        createMessageNotificationChannel(context);
+    }
+
+    @TargetApi(26)
+    private static void createForegroundNotificationChannel(Context context) {
+        NotificationManager notificationManager =
+                (NotificationManager) context.getSystemService(Context.NOTIFICATION_SERVICE);
+        String channelName = context.getResources().getString(R.string.channel_name_foreground);
+        String channelDescription = context.getResources().getString(R.string.channel_description_foreground);
+
+        NotificationChannel channel = new NotificationChannel(
+                NOTIFICATION_CHANNEL__FOREGROUND_SERVICE, channelName, NotificationManager.IMPORTANCE_MIN);
+        channel.setDescription(channelDescription);
+        channel.setShowBadge(false);
+        notificationManager.createNotificationChannel(channel);
+    }
+
+    @TargetApi(26)
+    private static void createMessageNotificationChannel(Context context) {
+        NotificationManager notificationManager =
+                (NotificationManager) context.getSystemService(Context.NOTIFICATION_SERVICE);
+        String channelName = context.getResources().getString(R.string.channel_name_message);
+        String channelDescription = context.getResources().getString(R.string.channel_description_message);
+
+        NotificationChannel channel = new NotificationChannel(
+                NOTIFICATION_CHANNEL__NEW_MESSAGE, channelName, NotificationManager.IMPORTANCE_DEFAULT);
+        channel.setDescription(channelDescription);
+        notificationManager.createNotificationChannel(channel);
+    }
 
     public static int directChatMessageReceived(Context context, DirectChat chat, String contactName, String body) {
         NotificationManagerCompat notificationManagerCompat = NotificationManagerCompat.from(context);
diff --git a/domain/src/main/java/org/mercury_im/messenger/ClientStateListener.java b/domain/src/main/java/org/mercury_im/messenger/ClientStateListener.java
new file mode 100644
index 0000000..61964d0
--- /dev/null
+++ b/domain/src/main/java/org/mercury_im/messenger/ClientStateListener.java
@@ -0,0 +1,8 @@
+package org.mercury_im.messenger;
+
+public interface ClientStateListener {
+
+    void onClientInForeground();
+
+    void onClientInBackground();
+}