diff --git a/android/app/build.gradle b/android/app/build.gradle
index cb41471..69f34ff 100644
--- a/android/app/build.gradle
+++ b/android/app/build.gradle
@@ -1,3 +1,11 @@
+plugins {
+    id 'com.android.application'
+    id 'kotlin-android'
+    id "org.jetbrains.kotlin.android"
+    id 'dev.flutter.flutter-gradle-plugin'
+    id 'com.google.gms.google-services'
+}
+
 def localProperties = new Properties()
 def localPropertiesFile = rootProject.file('local.properties')
 if (localPropertiesFile.exists()) {
@@ -6,11 +14,6 @@ if (localPropertiesFile.exists()) {
     }
 }
 
-def flutterRoot = localProperties.getProperty('flutter.sdk')
-if (flutterRoot == null) {
-    throw new GradleException("Flutter SDK not found. Define location with flutter.sdk in the local.properties file.")
-}
-
 def flutterVersionCode = localProperties.getProperty('flutter.versionCode')
 if (flutterVersionCode == null) {
     flutterVersionCode = '1'
@@ -27,11 +30,6 @@ if (keystorePropertiesFile.exists()) {
     keystoreProperties.load(new FileInputStream(keystorePropertiesFile))
 }
 
-apply plugin: 'com.android.application'
-apply plugin: 'com.google.gms.google-services'
-apply plugin: 'kotlin-android'
-apply from: "$flutterRoot/packages/flutter_tools/gradle/flutter.gradle"
-
 android {
     compileSdkVersion flutter.compileSdkVersion
     ndkVersion flutter.ndkVersion
@@ -109,6 +107,5 @@ flutter {
 }
 
 dependencies {
-    implementation "org.jetbrains.kotlin:kotlin-stdlib-jdk7:$kotlin_version"
     implementation 'com.android.support:multidex:1.0.3'
 }
diff --git a/android/build.gradle b/android/build.gradle
index e6aaae5..b42eb3a 100644
--- a/android/build.gradle
+++ b/android/build.gradle
@@ -1,17 +1,3 @@
-buildscript {
-    ext.kotlin_version = '1.7.10'
-    repositories {
-        google()
-        mavenCentral()
-    }
-
-    dependencies {
-        classpath 'com.android.tools.build:gradle:7.4.2'
-        classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"
-        classpath 'com.google.gms:google-services:4.4.1'
-    }
-}
-
 allprojects {
     repositories {
         google()
diff --git a/android/settings.gradle b/android/settings.gradle
index 44e62bc..c07940c 100644
--- a/android/settings.gradle
+++ b/android/settings.gradle
@@ -1,11 +1,26 @@
-include ':app'
+pluginManagement {
+    def flutterSdkPath = {
+        def properties = new Properties()
+        file("local.properties").withInputStream { properties.load(it) }
+        def flutterSdkPath = properties.getProperty("flutter.sdk")
+        assert flutterSdkPath != null, "flutter.sdk not set in local.properties"
+        return flutterSdkPath
+    }()
 
-def localPropertiesFile = new File(rootProject.projectDir, "local.properties")
-def properties = new Properties()
+    includeBuild("$flutterSdkPath/packages/flutter_tools/gradle")
 
-assert localPropertiesFile.exists()
-localPropertiesFile.withReader("UTF-8") { reader -> properties.load(reader) }
+    repositories {
+        google()
+        mavenCentral()
+        gradlePluginPortal()
+    }
+}
 
-def flutterSdkPath = properties.getProperty("flutter.sdk")
-assert flutterSdkPath != null, "flutter.sdk not set in local.properties"
-apply from: "$flutterSdkPath/packages/flutter_tools/gradle/app_plugin_loader.gradle"
+plugins {
+    id "dev.flutter.flutter-plugin-loader" version "1.0.0"
+    id "com.android.application" version "7.4.2" apply false
+    id "org.jetbrains.kotlin.android" version "1.7.10" apply false
+    id "com.google.gms.google-services" version "4.4.0" apply false
+}
+
+include ":app"
\ No newline at end of file
diff --git a/lib/app/cubit/app_cubit.dart b/lib/app/cubit/app_cubit.dart
index 5adfe25..a9825b3 100644
--- a/lib/app/cubit/app_cubit.dart
+++ b/lib/app/cubit/app_cubit.dart
@@ -8,7 +8,7 @@ class AppCubit extends Cubit<AppState> {
     required UserRepository userRepository,
   })  : _userRepository = userRepository,
         super(
-          userRepository.user.isNone
+          userRepository.user.isEmpty
               ? const AppState.unauthenticated()
               : AppState.newlyAuthenticated(userRepository.user),
         ) {
@@ -32,7 +32,7 @@ class AppCubit extends Cubit<AppState> {
   }
 
   void _onUserChanged(User user) {
-    if (user.isNone) {
+    if (user.isEmpty) {
       emit(const AppState.unauthenticated());
     } else if (state.isUnauthenticated) {
       emit(AppState.newlyAuthenticated(user));
@@ -44,7 +44,7 @@ class AppCubit extends Cubit<AppState> {
   void _onUserFailed(UserFailure failure) {
     final currentState = state;
     emit(AppState.failure(failure: failure, user: currentState.user));
-    if (failure.requiresReauthentication) {
+    if (failure.needsReauthentication) {
       emit(const AppState.unauthenticated());
     } else {
       emit(currentState);
diff --git a/lib/app/cubit/app_state.dart b/lib/app/cubit/app_state.dart
index 3392a27..621c1fb 100644
--- a/lib/app/cubit/app_state.dart
+++ b/lib/app/cubit/app_state.dart
@@ -17,8 +17,8 @@ extension AppStatusExtensions on AppStatus {
 final class AppState extends Equatable {
   const AppState._({
     required this.status,
-    this.user = User.none,
-    this.failure = UserFailure.none,
+    this.user = User.empty,
+    this.failure = UserFailure.empty,
   });
 
   const AppState.unauthenticated() : this._(status: AppStatus.unauthenticated);
diff --git a/lib/login/cubit/login_state.dart b/lib/login/cubit/login_state.dart
index ae31c02..8d6aa9d 100644
--- a/lib/login/cubit/login_state.dart
+++ b/lib/login/cubit/login_state.dart
@@ -18,7 +18,7 @@ final class LoginState extends Equatable {
   const LoginState._({
     this.status = LoginStatus.initial,
     this.signInMethod = SignInMethod.none,
-    this.failure = UserFailure.none,
+    this.failure = UserFailure.empty,
   });
 
   const LoginState.initial() : this._();
diff --git a/lib/profile/cubit/profile_cubit.dart b/lib/profile/cubit/profile_cubit.dart
index b15bc34..a85fe59 100644
--- a/lib/profile/cubit/profile_cubit.dart
+++ b/lib/profile/cubit/profile_cubit.dart
@@ -4,7 +4,7 @@ import 'package:user_repository/user_repository.dart';
 class ProfileCubit extends Cubit<User> {
   ProfileCubit({required UserRepository userRepository})
       : _userRepository = userRepository,
-        super(User.none) {
+        super(User.empty) {
     _watchUser();
   }
 
diff --git a/lib/quiz/cubit/quiz_cubit.dart b/lib/quiz/cubit/quiz_cubit.dart
index f6ba647..9ea2280 100644
--- a/lib/quiz/cubit/quiz_cubit.dart
+++ b/lib/quiz/cubit/quiz_cubit.dart
@@ -19,7 +19,7 @@ class QuizCubit extends Cubit<QuizState> {
     try {
       emit(state.fromQuizLoading());
       final quiz = await _quizzesRepository.getQuiz(quizId);
-      if (quiz.isNone) {
+      if (quiz.isEmpty) {
         emit(state.fromQuizEmpty());
         return;
       }
@@ -38,7 +38,7 @@ class QuizCubit extends Cubit<QuizState> {
   }
 
   void unselectOption() {
-    emit(state.copyWith(selectedOption: Option.none));
+    emit(state.copyWith(selectedOption: Option.empty));
   }
 
   void validateAnswer() {
diff --git a/lib/quiz/cubit/quiz_state.dart b/lib/quiz/cubit/quiz_state.dart
index 5d300f1..56962cd 100644
--- a/lib/quiz/cubit/quiz_state.dart
+++ b/lib/quiz/cubit/quiz_state.dart
@@ -5,10 +5,10 @@ enum QuizStatus { initial, loading, empty, loaded, failure }
 final class QuizState extends Equatable {
   const QuizState._({
     this.status = QuizStatus.initial,
-    this.quiz = Quiz.none,
-    this.selectedOption = Option.none,
+    this.quiz = Quiz.empty,
+    this.selectedOption = Option.empty,
     this.step = 0,
-    this.failure = QuizzesFailure.none,
+    this.failure = QuizzesFailure.empty,
   });
 
   const QuizState.initial() : this._();
@@ -57,5 +57,5 @@ extension QuizStateExtensions on QuizState {
   double get progress => step / steps;
 
   Question operator [](int step) =>
-      quiz.questions.isEmpty ? Question.none : quiz.questions[step - 1];
+      quiz.questions.isEmpty ? Question.empty : quiz.questions[step - 1];
 }
diff --git a/lib/quiz/view/quiz_page.dart b/lib/quiz/view/quiz_page.dart
index e0f865b..e44257c 100644
--- a/lib/quiz/view/quiz_page.dart
+++ b/lib/quiz/view/quiz_page.dart
@@ -91,7 +91,7 @@ class _QuizBodyState extends State<QuizBody> {
           listenWhen: (previous, current) =>
               previous.quiz.id != current.quiz.id,
           listener: (_, state) {
-            if (state.quiz.isNone) {
+            if (state.quiz.isEmpty) {
               context.read<VoidCallback>()();
             }
           },
@@ -110,7 +110,7 @@ class _QuizBodyState extends State<QuizBody> {
           listenWhen: (previous, current) =>
               previous.selectedOption != current.selectedOption,
           listener: (_, state) {
-            if (state.selectedOption.isNotNone) {
+            if (state.selectedOption.isNotEmpty) {
               context.showScrollControlledBottomSheet<void>(
                 builder: (_) {
                   return BlocProvider.value(
diff --git a/lib/topics/cubit/topics_state.dart b/lib/topics/cubit/topics_state.dart
index 88d29b0..5c93f27 100644
--- a/lib/topics/cubit/topics_state.dart
+++ b/lib/topics/cubit/topics_state.dart
@@ -4,10 +4,10 @@ enum TopicsStatus { initial, loading, empty, loaded, failure }
 
 final class TopicsState extends Equatable {
   const TopicsState._({
-    this.user = User.none,
+    this.user = User.empty,
     this.status = TopicsStatus.initial,
     this.topics = const [],
-    this.failure = TopicsFailure.none,
+    this.failure = TopicsFailure.empty,
   });
 
   const TopicsState.initial() : this._();
diff --git a/lib/topics/view/topics_flow.dart b/lib/topics/view/topics_flow.dart
index 228ca75..54568c6 100644
--- a/lib/topics/view/topics_flow.dart
+++ b/lib/topics/view/topics_flow.dart
@@ -27,7 +27,7 @@ List<Page<dynamic>> onGenerateTopicsPages(
 
 class TopicsFlowState extends Equatable {
   const TopicsFlowState._({
-    this.selectedTopic = Topic.none,
+    this.selectedTopic = Topic.empty,
     this.selectedQuizId = '',
   });
 
@@ -36,7 +36,7 @@ class TopicsFlowState extends Equatable {
   final Topic selectedTopic;
   final String selectedQuizId;
 
-  bool get hasTopicSelected => selectedTopic.isNotNone;
+  bool get hasTopicSelected => selectedTopic.isNotEmpty;
   bool get hasQuizSelected => selectedQuizId.isNotEmpty;
 
   @override
diff --git a/packages/app_core/lib/src/failure.dart b/packages/app_core/lib/src/failure.dart
index b2eb624..03d502e 100644
--- a/packages/app_core/lib/src/failure.dart
+++ b/packages/app_core/lib/src/failure.dart
@@ -1,3 +1,5 @@
 abstract class Failure implements Exception {
   const Failure();
+
+  bool get needsReauthentication => false;
 }
diff --git a/packages/quizzes_repository/lib/src/failures.dart b/packages/quizzes_repository/lib/src/failures.dart
index 955e73c..a792557 100644
--- a/packages/quizzes_repository/lib/src/failures.dart
+++ b/packages/quizzes_repository/lib/src/failures.dart
@@ -5,11 +5,11 @@ class QuizzesFailure extends Failure {
 
   factory QuizzesFailure.fromGetQuiz() => const GetQuizFailure();
 
-  static const none = QuizzesNoFailure();
+  static const empty = EmptyQuizzesFailure();
 }
 
-class QuizzesNoFailure extends QuizzesFailure {
-  const QuizzesNoFailure() : super._();
+class EmptyQuizzesFailure extends QuizzesFailure {
+  const EmptyQuizzesFailure() : super._();
 }
 
 class GetQuizFailure extends QuizzesFailure {
diff --git a/packages/quizzes_repository/lib/src/models/models.dart b/packages/quizzes_repository/lib/src/models/models.dart
index db99326..bbbc818 100644
--- a/packages/quizzes_repository/lib/src/models/models.dart
+++ b/packages/quizzes_repository/lib/src/models/models.dart
@@ -17,7 +17,7 @@ class Option extends Equatable {
   final String detail;
   final bool? correct;
 
-  static const none = Option(value: '', detail: '', correct: null);
+  static const empty = Option(value: '', detail: '', correct: null);
 
   @override
   List<Object?> get props => [value, detail, correct];
@@ -26,7 +26,7 @@ class Option extends Equatable {
 }
 
 extension OptionExtensions on Option {
-  bool get isNotNone => this != Option.none;
+  bool get isNotEmpty => this != Option.empty;
 }
 
 @JsonSerializable(createToJson: false)
@@ -40,7 +40,7 @@ class Question extends Equatable {
   @JsonKey(defaultValue: <Option>[])
   final List<Option> options;
 
-  static const none = Question(text: '', options: []);
+  static const empty = Question(text: '', options: []);
 
   @override
   List<Object?> get props => [text, options];
@@ -69,7 +69,7 @@ class Quiz extends Equatable {
   @JsonKey(defaultValue: <Question>[])
   final List<Question> questions;
 
-  static const none = Quiz(
+  static const empty = Quiz(
     id: '',
     title: '',
     description: '',
@@ -92,5 +92,5 @@ class Quiz extends Equatable {
 }
 
 extension QuizExtensions on Quiz {
-  bool get isNone => this == Quiz.none;
+  bool get isEmpty => this == Quiz.empty;
 }
diff --git a/packages/quizzes_repository/lib/src/quizzes_repository.dart b/packages/quizzes_repository/lib/src/quizzes_repository.dart
index 23aa1fe..fccfd68 100644
--- a/packages/quizzes_repository/lib/src/quizzes_repository.dart
+++ b/packages/quizzes_repository/lib/src/quizzes_repository.dart
@@ -15,7 +15,7 @@ class QuizzesRepository {
       if (doc.exists) {
         return Quiz.fromJson(doc.data()!);
       }
-      return Quiz.none;
+      return Quiz.empty;
     } on FirebaseException {
       throw QuizzesFailure.fromGetQuiz();
     }
diff --git a/packages/topics_repository/lib/src/failures.dart b/packages/topics_repository/lib/src/failures.dart
index fd116dd..a14e94f 100644
--- a/packages/topics_repository/lib/src/failures.dart
+++ b/packages/topics_repository/lib/src/failures.dart
@@ -5,11 +5,11 @@ class TopicsFailure extends Failure {
 
   factory TopicsFailure.fromGetTopics() => const GetTopicsFailure();
 
-  static const none = TopicsNoFailure();
+  static const empty = EmptyTopicsFailure();
 }
 
-class TopicsNoFailure extends TopicsFailure {
-  const TopicsNoFailure() : super._();
+class EmptyTopicsFailure extends TopicsFailure {
+  const EmptyTopicsFailure() : super._();
 }
 
 class GetTopicsFailure extends TopicsFailure {
diff --git a/packages/topics_repository/lib/src/models/models.dart b/packages/topics_repository/lib/src/models/models.dart
index 111bfe7..591bf4b 100644
--- a/packages/topics_repository/lib/src/models/models.dart
+++ b/packages/topics_repository/lib/src/models/models.dart
@@ -16,7 +16,7 @@ class Quiz extends Equatable {
   final String title;
   final String description;
 
-  static const none = Quiz(
+  static const empty = Quiz(
     id: '',
     title: '',
     description: '',
@@ -46,7 +46,7 @@ class Topic extends Equatable {
   final String imageName;
   final List<Quiz> quizzes;
 
-  static const none = Topic(
+  static const empty = Topic(
     id: '',
     title: '',
     description: '',
@@ -61,8 +61,8 @@ class Topic extends Equatable {
 }
 
 extension TopicExtensions on Topic {
-  bool get isNone => this == Topic.none;
-  bool get isNotNone => !isNone;
+  bool get isEmpty => this == Topic.empty;
+  bool get isNotEmpty => !isEmpty;
 
   int get totalQuizzes => quizzes.length;
 
diff --git a/packages/user_repository/lib/src/failures.dart b/packages/user_repository/lib/src/failures.dart
index f8e5f1c..9371738 100644
--- a/packages/user_repository/lib/src/failures.dart
+++ b/packages/user_repository/lib/src/failures.dart
@@ -13,19 +13,18 @@ class UserFailure extends Failure {
   factory UserFailure.fromSignInWithAppleNotSupported() =>
       const AppleSignInNotSupportedFailure();
 
-  static const none = UserNoFailure();
-
-  bool get requiresReauthentication {
-    return this is AuthUserChangesFailure;
-  }
+  static const empty = EmptyUserFailure();
 }
 
-class UserNoFailure extends UserFailure {
-  const UserNoFailure() : super._();
+class EmptyUserFailure extends UserFailure {
+  const EmptyUserFailure() : super._();
 }
 
 class AuthUserChangesFailure extends UserFailure {
   const AuthUserChangesFailure() : super._();
+
+  @override
+  bool get needsReauthentication => true;
 }
 
 class SignOutFailure extends UserFailure {
diff --git a/packages/user_repository/lib/src/models/models.dart b/packages/user_repository/lib/src/models/models.dart
index 130acea..593d6ad 100644
--- a/packages/user_repository/lib/src/models/models.dart
+++ b/packages/user_repository/lib/src/models/models.dart
@@ -40,7 +40,7 @@ class User extends Equatable {
   @timestamp
   final DateTime? lastSignInAt;
 
-  static const none = User(uid: '');
+  static const empty = User(uid: '');
 
   @override
   List<Object?> get props => [
@@ -59,7 +59,7 @@ class User extends Equatable {
 }
 
 extension UserExtensions on User {
-  bool get isNone => this == User.none;
+  bool get isEmpty => this == User.empty;
 
   int totalCompletedQuizzesByTopic(String topicId) =>
       completedQuizzes[topicId]?.length ?? 0;
diff --git a/packages/user_repository/lib/src/user_repository.dart b/packages/user_repository/lib/src/user_repository.dart
index a8ee9fd..38b1fb0 100644
--- a/packages/user_repository/lib/src/user_repository.dart
+++ b/packages/user_repository/lib/src/user_repository.dart
@@ -21,20 +21,20 @@ class UserRepository {
 
   late final ValueStream<User> _user;
 
-  /// Current user as a stream.
+  /// Current [User] as a stream.
   Stream<User> get watchUser => _user.asBroadcastStream();
 
-  /// Gets the current user synchronously.
-  User get user => _user.valueOrNull ?? User.none;
+  /// Gets the current [User] synchronously.
+  User get user => _user.valueOrNull ?? User.empty;
 
-  /// Gets the initial `watchUser` emission.
+  /// Gets the initial [watchUser] emission.
   ///
-  /// Returns `User.none` when an error occurs.
+  /// Returns [User.empty] when an error occurs.
   Future<User> getOpeningUser() {
-    return watchUser.first.catchError((Object _) => User.none);
+    return watchUser.first.catchError((Object _) => User.empty);
   }
 
-  /// Signs the user in anonymously.
+  /// Signs the [User] in anonymously.
   Future<void> signInAnonymously() async {
     try {
       final userCredential = await _firebaseAuth.signInAnonymously();
@@ -45,7 +45,7 @@ class UserRepository {
     }
   }
 
-  /// Signs the user in using google provider.
+  /// Signs the [User] in using google provider.
   Future<void> signInWithGoogle() async {
     try {
       final googleSignInAccount = await _googleSignIn.signIn();
@@ -68,7 +68,7 @@ class UserRepository {
     }
   }
 
-  /// Signs the user in using apple provider.
+  /// Signs the [User] in using apple provider.
   Future<void> signInWithApple() async {
     try {
       // To prevent replay attacks with the credential returned from Apple, we
@@ -108,7 +108,7 @@ class UserRepository {
     }
   }
 
-  /// Logs out the current user.
+  /// Signs out the current [User].
   Future<void> signOut() async {
     try {
       await Future.wait([
@@ -120,7 +120,7 @@ class UserRepository {
     }
   }
 
-  /// Marks a quiz as completed.
+  /// Marks a `Quiz` as completed.
   ///
   /// It also increments the total no of completed quizzes.
   Future<void> markQuizCompleted({
@@ -166,14 +166,14 @@ extension _FirebaseAuthExtensions on FirebaseAuth {
           .switchMap<User>(
             (firebaseUser) async* {
               if (firebaseUser == null) {
-                yield User.none;
+                yield User.empty;
                 return;
               }
 
               yield* firestore.userDoc(firebaseUser.uid).snapshots().map(
                     (snapshot) => snapshot.exists
                         ? User.fromJson(snapshot.data()!)
-                        : User.none,
+                        : User.empty,
                   );
             },
           )