diff --git a/app/build.gradle b/app/build.gradle
index 79b7ad2..3e34bb9 100644
--- a/app/build.gradle
+++ b/app/build.gradle
@@ -19,6 +19,11 @@ android {
             proguardFiles getDefaultProguardFile('proguard-android-optimize.txt'), 'proguard-rules.pro'
         }
     }
+    compileOptions {
+        sourceCompatibility = '1.8'
+        targetCompatibility = '1.8'
+    }
+    buildToolsVersion = '29.0.1'
 }
 
 dependencies {
diff --git a/app/src/main/java/lu/circl/mispbump/activities/PreferenceActivity.java b/app/src/main/java/lu/circl/mispbump/activities/PreferenceActivity.java
index 69b6534..7af22e5 100644
--- a/app/src/main/java/lu/circl/mispbump/activities/PreferenceActivity.java
+++ b/app/src/main/java/lu/circl/mispbump/activities/PreferenceActivity.java
@@ -8,7 +8,6 @@ import androidx.appcompat.app.AppCompatActivity;
 import androidx.appcompat.widget.Toolbar;
 import androidx.fragment.app.FragmentManager;
 import androidx.fragment.app.FragmentTransaction;
-import androidx.preference.Preference;
 import androidx.preference.PreferenceFragmentCompat;
 
 import lu.circl.mispbump.R;
@@ -41,13 +40,7 @@ public class PreferenceActivity extends AppCompatActivity {
         @Override
         public void onCreatePreferences(Bundle savedInstanceState, String rootKey) {
             setPreferencesFromResource(R.xml.preference_screen_main, rootKey);
-
-            findPreference("PREF_DELETE_ALL_SYNCS").setOnPreferenceClickListener(new Preference.OnPreferenceClickListener() {
-                @Override
-                public boolean onPreferenceClick(Preference preference) {
-                    return true;
-                }
-            });
+            findPreference("PREF_DELETE_ALL_SYNCS").setOnPreferenceClickListener(preference -> true);
         }
     }
 }