diff --git a/app/src/main/java/de/gymnasium_beetzendorf/vertretungsplan/DatabaseHandler.java b/app/src/main/java/de/gymnasium_beetzendorf/vertretungsplan/DatabaseHandler.java
index 9b33635..e60b5a8 100644
--- a/app/src/main/java/de/gymnasium_beetzendorf/vertretungsplan/DatabaseHandler.java
+++ b/app/src/main/java/de/gymnasium_beetzendorf/vertretungsplan/DatabaseHandler.java
@@ -7,7 +7,9 @@
 import android.database.Cursor;
 import android.database.sqlite.SQLiteDatabase;
 import android.database.sqlite.SQLiteOpenHelper;
-import android.preference.PreferenceManager;
+
+import androidx.preference.PreferenceManager;
+
 import android.util.Log;
 
 import java.text.ParseException;
diff --git a/app/src/main/java/de/gymnasium_beetzendorf/vertretungsplan/XmlParser.java b/app/src/main/java/de/gymnasium_beetzendorf/vertretungsplan/XmlParser.java
index 92bf8f8..6d59386 100644
--- a/app/src/main/java/de/gymnasium_beetzendorf/vertretungsplan/XmlParser.java
+++ b/app/src/main/java/de/gymnasium_beetzendorf/vertretungsplan/XmlParser.java
@@ -2,7 +2,9 @@
 
 import android.content.Context;
 import android.content.SharedPreferences;
-import android.preference.PreferenceManager;
+
+import androidx.preference.PreferenceManager;
+
 import android.util.Log;
 
 import org.xmlpull.v1.XmlPullParser;
diff --git a/app/src/main/java/de/gymnasium_beetzendorf/vertretungsplan/activity/AboutActivity.java b/app/src/main/java/de/gymnasium_beetzendorf/vertretungsplan/activity/AboutActivity.java
index 60700d5..1b6bfea 100644
--- a/app/src/main/java/de/gymnasium_beetzendorf/vertretungsplan/activity/AboutActivity.java
+++ b/app/src/main/java/de/gymnasium_beetzendorf/vertretungsplan/activity/AboutActivity.java
@@ -24,7 +24,7 @@ protected int getLayoutId() {
 
     @Override
     protected Toolbar getToolbar() {
-        return (Toolbar) findViewById(R.id.mainToolbar);
+        return findViewById(R.id.mainToolbar);
     }
 
     @Override
@@ -42,7 +42,7 @@ protected void onCreate(Bundle savedInstanceState) {
         }
 
         if (packageInfo != null) {
-            mVersionTextView.setText(String.format(getString(R.string.version_number), packageInfo.versionName, packageInfo.versionCode));
+            mVersionTextView.setText(String.format(getString(R.string.version_number), packageInfo.versionName, packageInfo.getLongVersionCode()));
         } else {
             mVersionTextView.setText(R.string.version_number_not_found);
         }
diff --git a/app/src/main/java/de/gymnasium_beetzendorf/vertretungsplan/fragment/ChooseFragment.java b/app/src/main/java/de/gymnasium_beetzendorf/vertretungsplan/fragment/ChooseFragment.java
index 10d6799..0ca7b58 100644
--- a/app/src/main/java/de/gymnasium_beetzendorf/vertretungsplan/fragment/ChooseFragment.java
+++ b/app/src/main/java/de/gymnasium_beetzendorf/vertretungsplan/fragment/ChooseFragment.java
@@ -4,16 +4,19 @@
 
 import androidx.annotation.NonNull;
 import androidx.fragment.app.Fragment;
+
 import android.content.BroadcastReceiver;
 import android.content.Context;
 import android.content.Intent;
 import android.content.IntentFilter;
 import android.content.SharedPreferences;
 import android.os.Bundle;
-import android.preference.PreferenceManager;
+
+import androidx.preference.PreferenceManager;
 import androidx.annotation.Nullable;
 import androidx.coordinatorlayout.widget.CoordinatorLayout;
 import androidx.localbroadcastmanager.content.LocalBroadcastManager;
+
 import android.view.LayoutInflater;
 import android.view.View;
 import android.view.ViewGroup;
@@ -73,7 +76,7 @@ protected SharedPreferences getSharedPreferences(Context context) {
     }
 
     protected CoordinatorLayout getCoordinatorLayout() {
-        return (CoordinatorLayout) activity.findViewById(R.id.welcome_coordinator);
+        return activity.findViewById(R.id.welcome_coordinator);
     }
 
     protected abstract String getNextButtonText();