diff --git a/lib/ui/tools/app_lock.dart b/lib/ui/tools/app_lock.dart
index 3e427e93d7..2e7e0f54b1 100644
--- a/lib/ui/tools/app_lock.dart
+++ b/lib/ui/tools/app_lock.dart
@@ -1,11 +1,8 @@
-// @dart=2.9
-
 import 'dart:async';
 
-import 'package:ente_auth/l10n/l10n.dart';
 import 'package:ente_auth/locale.dart';
 import 'package:flutter/material.dart';
-import 'package:flutter_localizations/flutter_localizations.dart';
+import 'package:flutter_gen/gen_l10n/app_localizations.dart';
 
 /// A widget which handles app lifecycle events for showing and hiding a lock screen.
 /// This should wrap around a `MyApp` widget (or equivalent).
@@ -30,26 +27,28 @@ import 'package:flutter_localizations/flutter_localizations.dart';
 
 // ignore_for_file: unnecessary_this, library_private_types_in_public_api
 class AppLock extends StatefulWidget {
-  final Widget Function(Object) builder;
+  final Widget Function(Object?) builder;
   final Widget lockScreen;
   final bool enabled;
   final Duration backgroundLockLatency;
-  final ThemeData darkTheme;
-  final ThemeData lightTheme;
+  final ThemeData? darkTheme;
+  final ThemeData? lightTheme;
+  final ThemeMode savedThemeMode;
   final Locale locale;
 
   const AppLock({
-    Key key,
-    @required this.builder,
-    @required this.lockScreen,
+    Key? key,
+    required this.builder,
+    required this.lockScreen,
+    required this.savedThemeMode,
     this.enabled = true,
+    this.locale = const Locale('en', 'US'),
     this.backgroundLockLatency = const Duration(seconds: 0),
     this.darkTheme,
     this.lightTheme,
-    this.locale,
   }) : super(key: key);
 
-  static _AppLockState of(BuildContext context) =>
+  static _AppLockState? of(BuildContext context) =>
       context.findAncestorStateOfType<_AppLockState>();
 
   @override
@@ -59,11 +58,11 @@ class AppLock extends StatefulWidget {
 class _AppLockState extends State<AppLock> with WidgetsBindingObserver {
   static final GlobalKey<NavigatorState> _navigatorKey = GlobalKey();
 
-  bool _didUnlockForAppLaunch;
-  bool _isLocked;
-  bool _enabled;
+  late bool _didUnlockForAppLaunch;
+  late bool _isLocked;
+  late bool _enabled;
 
-  Timer _backgroundLockLatencyTimer;
+  Timer? _backgroundLockLatencyTimer;
 
   @override
   void initState() {
@@ -109,17 +108,14 @@ class _AppLockState extends State<AppLock> with WidgetsBindingObserver {
     return MaterialApp(
       home: this.widget.enabled ? this._lockScreen : this.widget.builder(null),
       navigatorKey: _navigatorKey,
-      themeMode: ThemeMode.system,
+      themeMode: widget.savedThemeMode,
       theme: widget.lightTheme,
       darkTheme: widget.darkTheme,
       locale: widget.locale,
       supportedLocales: appSupportedLocales,
       localeListResolutionCallback: localResolutionCallBack,
       localizationsDelegates: const [
-        AppLocalizations.delegate,
-        GlobalMaterialLocalizations.delegate,
-        GlobalCupertinoLocalizations.delegate,
-        GlobalWidgetsLocalizations.delegate,
+        ...AppLocalizations.localizationsDelegates,
       ],
       onGenerateRoute: (settings) {
         switch (settings.name) {
@@ -153,7 +149,7 @@ class _AppLockState extends State<AppLock> with WidgetsBindingObserver {
   /// when built. Use this when you want to inject objects created from the
   /// [lockScreen] in to the rest of your app so you can better guarantee that some
   /// objects, services or databases are already instantiated before using them.
-  void didUnlock([Object args]) {
+  void didUnlock([Object? args]) {
     if (this._didUnlockForAppLaunch) {
       this._didUnlockOnAppPaused();
     } else {
@@ -192,17 +188,17 @@ class _AppLockState extends State<AppLock> with WidgetsBindingObserver {
   /// Manually show the [lockScreen].
   Future<void> showLockScreen() {
     this._isLocked = true;
-    return _navigatorKey.currentState.pushNamed('/lock-screen');
+    return _navigatorKey.currentState!.pushNamed('/lock-screen');
   }
 
-  void _didUnlockOnAppLaunch(Object args) {
+  void _didUnlockOnAppLaunch(Object? args) {
     this._didUnlockForAppLaunch = true;
-    _navigatorKey.currentState
+    _navigatorKey.currentState!
         .pushReplacementNamed('/unlocked', arguments: args);
   }
 
   void _didUnlockOnAppPaused() {
     this._isLocked = false;
-    _navigatorKey.currentState.pop();
+    _navigatorKey.currentState!.pop();
   }
 }