diff --git a/app/src/androidTest/java/org/secuso/privacyfriendlybattleship/ApplicationTest.java b/app/src/androidTest/java/org/secuso/privacyfriendlybattleship/ApplicationTest.java
deleted file mode 100644
index 2d5d160..0000000
--- a/app/src/androidTest/java/org/secuso/privacyfriendlybattleship/ApplicationTest.java
+++ /dev/null
@@ -1,13 +0,0 @@
-package org.secuso.privacyfriendlybattleship;
-
-import android.app.Application;
-import android.test.ApplicationTestCase;
-
-/**
- * <a href="http://d.android.com/tools/testing/testing_android.html">Testing Fundamentals</a>
- */
-public class ApplicationTest extends ApplicationTestCase<Application> {
-    public ApplicationTest() {
-        super(Application.class);
-    }
-}
\ No newline at end of file
diff --git a/app/src/main/res/layout-land/content_main.xml b/app/src/main/res/layout-land/content_main.xml
index 181d168..2316b12 100644
--- a/app/src/main/res/layout-land/content_main.xml
+++ b/app/src/main/res/layout-land/content_main.xml
@@ -42,7 +42,7 @@
             android:layout_width="wrap_content"
             android:layout_height="wrap_content"
             android:layout_marginTop="@dimen/activity_vertical_margin"
-            android:src="@drawable/ic_keyboard_arrow_left_black_24dp"
+            app:srcCompat="@drawable/ic_keyboard_arrow_left_black_24dp"
             android:layout_alignParentTop="true"
             android:padding="@dimen/activity_vertical_margin"
             android:layout_centerHorizontal="true"
diff --git a/app/src/main/res/layout-xlarge/content_main.xml b/app/src/main/res/layout-xlarge/content_main.xml
index e6c747c..b43d721 100644
--- a/app/src/main/res/layout-xlarge/content_main.xml
+++ b/app/src/main/res/layout-xlarge/content_main.xml
@@ -41,7 +41,7 @@
             android:id="@+id/mode_arrow_left"
             android:layout_width="wrap_content"
             android:layout_height="wrap_content"
-            android:src="@drawable/ic_keyboard_arrow_left_black_24dp"
+            app:srcCompat="@drawable/ic_keyboard_arrow_left_black_24dp"
             android:layout_alignParentLeft="true"
             android:layout_alignParentStart="true"
             android:padding="@dimen/activity_horizontal_margin"
diff --git a/app/src/main/res/layout/content_main.xml b/app/src/main/res/layout/content_main.xml
index cb164db..965b6ce 100644
--- a/app/src/main/res/layout/content_main.xml
+++ b/app/src/main/res/layout/content_main.xml
@@ -48,7 +48,7 @@
             android:layout_marginStart="@dimen/activity_horizontal_margin"
             android:onClick="onClick"
             android:padding="@dimen/activity_horizontal_margin"
-            android:src="@drawable/ic_keyboard_arrow_left_black_24dp" />
+            app:srcCompat="@drawable/ic_keyboard_arrow_left_black_24dp" />
 
         <ImageView
             android:id="@+id/mode_arrow_right"