diff --git a/.github/workflows/run-tests.yml b/.github/workflows/run-tests.yml
index 7640510b..de461b9c 100644
--- a/.github/workflows/run-tests.yml
+++ b/.github/workflows/run-tests.yml
@@ -19,7 +19,7 @@ jobs:
     strategy:
       fail-fast: true
       matrix:
-        pkg: [pubnub, pubnub_flutter]
+        pkg: [pubnub]
     steps:
       - name: Checkout repository
         uses: actions/checkout@v3
@@ -40,7 +40,7 @@ jobs:
           restore-keys: |
             ${{ runner.os }}-${{ matrix.pkg }}-
       - name: Setup Dart stable
-        uses: dart-lang/setup-dart@v1.3
+        uses: dart-lang/setup-dart@v1.5.0
       - name: "Build and run tests for '${{ matrix.pkg }}'"
         env:
           PKG: ${{ matrix.pkg }}
@@ -51,7 +51,7 @@ jobs:
             git clone https://github.com/flutter/flutter.git -b stable "$FLUTTER_PATH"
             export PATH="$PATH:$FLUTTER_PATH/bin"
           fi
-          dart pub global activate derry 1.3.0
+          dart pub global activate derry 1.5.0
           cd "${{ github.workspace }}/${{ matrix.pkg }}"
           [[ ${{ matrix.pkg }} == "pubnub_flutter" ]] && flutter pub get || dart pub get
           derry validate analysis
diff --git a/.pubnub.yml b/.pubnub.yml
index d9d61db9..2d01df2c 100644
--- a/.pubnub.yml
+++ b/.pubnub.yml
@@ -1,5 +1,10 @@
 ---
 changelog:
+  - date: 2023-05-18
+    version: v4.2.3
+    changes:
+      - type: bug
+        text: "Fixes issue of losing timetoken value precision in web environment."
   - date: 2022-11-14
     version: v4.2.2
     changes:
@@ -415,7 +420,7 @@ supported-platforms:
     platforms:
       - "Dart SDK >=2.6.0 <3.0.0"
     version: "PubNub Dart SDK"
-version: "4.2.2"
+version: "4.2.3"
 sdks:
   -
     full-name: PubNub Dart SDK
diff --git a/acceptance_tests/lib/src/hooks/mock_server_hook.dart b/acceptance_tests/lib/src/hooks/mock_server_hook.dart
index f2f016c6..a0cbe7d2 100644
--- a/acceptance_tests/lib/src/hooks/mock_server_hook.dart
+++ b/acceptance_tests/lib/src/hooks/mock_server_hook.dart
@@ -13,13 +13,17 @@ class MockServerHook extends Hook {
     Iterable<Tag> tags,
   ) async {
     try {
-      var tagParts = tags.firstWhere((element) => element.name.startsWith('@contract=')).name.split('=');
+      var tagParts = tags
+          .firstWhere((element) => element.name.startsWith('@contract='))
+          .name
+          .split('=');
 
       var contract = tagParts.skip(1).first;
 
       // await Future.delayed(Duration(seconds: 3));
 
-      var res = await http.get(Uri.parse('http://localhost:8090/init?__contract__script__=$contract'));
+      var res = await http.get(Uri.parse(
+          'http://localhost:8090/init?__contract__script__=$contract'));
 
       // check for 200 response and fail scenario if not 200
 
@@ -35,8 +39,8 @@ class MockServerHook extends Hook {
   int myData = 0;
 
   @override
-  Future<StepResult?> onAfterStep(
-      covariant PubNubWorld world, ScenarioRunnable scenario, String step, StepResult stepResult) async {
+  Future<StepResult?> onAfterStep(covariant PubNubWorld world,
+      ScenarioRunnable scenario, String step, StepResult stepResult) async {
     // print(
     //     'Hook step: $step, result: ${stepResult.result} ${stepResult.resultReason}');
 
@@ -58,12 +62,12 @@ class MockServerHook extends Hook {
         //     '[Hook] x ${failedExp.length}, . ${pendingExp.length}, v ${succeededExp.length}');
 
         if (failedExp.isNotEmpty) {
-          return StepResult(
-              stepResult.elapsedMilliseconds, StepExecutionResult.fail, 'Failed expectations: $failedExp.');
+          return StepResult(stepResult.elapsedMilliseconds,
+              StepExecutionResult.fail, 'Failed expectations: $failedExp.');
         }
       } catch (e) {
-        return StepResult(
-            stepResult.elapsedMilliseconds, StepExecutionResult.error, 'Unable to verify expectations: $e.');
+        return StepResult(stepResult.elapsedMilliseconds,
+            StepExecutionResult.error, 'Unable to verify expectations: $e.');
       }
     }
 
diff --git a/acceptance_tests/lib/src/parameters/keyset.dart b/acceptance_tests/lib/src/parameters/keyset.dart
index cbb2bd39..eda159de 100644
--- a/acceptance_tests/lib/src/parameters/keyset.dart
+++ b/acceptance_tests/lib/src/parameters/keyset.dart
@@ -35,5 +35,6 @@ class KeysetParameter extends CustomParameter<Keyset> {
                 cipherKey: CipherKey.fromUtf8('invalid'),
               );
           }
+          return null;
         });
 }
diff --git a/acceptance_tests/lib/src/reporter.dart b/acceptance_tests/lib/src/reporter.dart
index 5c8c7eab..af4050a9 100644
--- a/acceptance_tests/lib/src/reporter.dart
+++ b/acceptance_tests/lib/src/reporter.dart
@@ -142,6 +142,7 @@ class PubNubReporter extends Reporter {
     print('');
     print('  $scenarioCount scenarios executed');
     print('${Color.PASS}✓${Color.RESET} $passedScenarioCount scenarios passed');
-    print('${Color.FAIL}x${Color.RESET} ${scenarioCount - passedScenarioCount} scenarios failed');
+    print(
+        '${Color.FAIL}x${Color.RESET} ${scenarioCount - passedScenarioCount} scenarios failed');
   }
 }
diff --git a/acceptance_tests/lib/src/steps/pam_v3/step_then_an_auth_error.dart b/acceptance_tests/lib/src/steps/pam_v3/step_then_an_auth_error.dart
index cbebcfe8..c0d19feb 100644
--- a/acceptance_tests/lib/src/steps/pam_v3/step_then_an_auth_error.dart
+++ b/acceptance_tests/lib/src/steps/pam_v3/step_then_an_auth_error.dart
@@ -1,7 +1,6 @@
 //
 import 'package:gherkin/gherkin.dart';
 import 'package:pubnub/core.dart';
-import 'package:pubnub/pubnub.dart';
 import 'package:test/test.dart';
 
 import '../../world.dart';
diff --git a/acceptance_tests/lib/src/steps/pam_v3/step_then_error_detail_message_is_not_empty.dart b/acceptance_tests/lib/src/steps/pam_v3/step_then_error_detail_message_is_not_empty.dart
index f196c2f1..d3d252e8 100644
--- a/acceptance_tests/lib/src/steps/pam_v3/step_then_error_detail_message_is_not_empty.dart
+++ b/acceptance_tests/lib/src/steps/pam_v3/step_then_error_detail_message_is_not_empty.dart
@@ -1,5 +1,4 @@
 import 'package:gherkin/gherkin.dart';
-import 'package:pubnub/pubnub.dart';
 import 'package:test/test.dart';
 
 import '../../world.dart';
diff --git a/acceptance_tests/lib/src/steps/pam_v3/step_then_error_is_returned.dart b/acceptance_tests/lib/src/steps/pam_v3/step_then_error_is_returned.dart
index f3e9674b..c0286a46 100644
--- a/acceptance_tests/lib/src/steps/pam_v3/step_then_error_is_returned.dart
+++ b/acceptance_tests/lib/src/steps/pam_v3/step_then_error_is_returned.dart
@@ -1,5 +1,4 @@
 import 'package:gherkin/gherkin.dart';
-import 'package:pubnub/pubnub.dart';
 import 'package:test/test.dart';
 
 import '../../world.dart';
diff --git a/acceptance_tests/lib/src/steps/pam_v3/step_when_i_attempt_publish_with_authToken.dart b/acceptance_tests/lib/src/steps/pam_v3/step_when_i_attempt_publish_with_authToken.dart
index bc181225..a341570e 100644
--- a/acceptance_tests/lib/src/steps/pam_v3/step_when_i_attempt_publish_with_authToken.dart
+++ b/acceptance_tests/lib/src/steps/pam_v3/step_when_i_attempt_publish_with_authToken.dart
@@ -1,6 +1,5 @@
 import 'package:gherkin/gherkin.dart';
 import 'package:pubnub/core.dart';
-import 'package:pubnub/pubnub.dart';
 import 'package:test/expect.dart';
 
 import '../../world.dart';
diff --git a/acceptance_tests/lib/src/steps/step_then_i_receive_successful_response.dart b/acceptance_tests/lib/src/steps/step_then_i_receive_successful_response.dart
index 0a8405f5..2382a9be 100644
--- a/acceptance_tests/lib/src/steps/step_then_i_receive_successful_response.dart
+++ b/acceptance_tests/lib/src/steps/step_then_i_receive_successful_response.dart
@@ -1,4 +1,3 @@
-import 'dart:io';
 
 import 'package:gherkin/gherkin.dart';
 import 'package:pubnub/pubnub.dart';
diff --git a/acceptance_tests/lib/src/steps/step_when_i_request_current_time.dart b/acceptance_tests/lib/src/steps/step_when_i_request_current_time.dart
index 56084e61..e7eea3d1 100644
--- a/acceptance_tests/lib/src/steps/step_when_i_request_current_time.dart
+++ b/acceptance_tests/lib/src/steps/step_when_i_request_current_time.dart
@@ -1,5 +1,4 @@
 import 'package:gherkin/gherkin.dart';
-import 'package:pubnub/pubnub.dart';
 
 import '../world.dart';
 
diff --git a/acceptance_tests/lib/src/steps/step_when_i_send_a_signal.dart b/acceptance_tests/lib/src/steps/step_when_i_send_a_signal.dart
index 8c17a608..3ae01953 100644
--- a/acceptance_tests/lib/src/steps/step_when_i_send_a_signal.dart
+++ b/acceptance_tests/lib/src/steps/step_when_i_send_a_signal.dart
@@ -1,5 +1,4 @@
 import 'package:gherkin/gherkin.dart';
-import 'package:pubnub/pubnub.dart';
 
 import '../world.dart';
 
diff --git a/acceptance_tests/lib/src/steps/step_when_i_subscribe.dart b/acceptance_tests/lib/src/steps/step_when_i_subscribe.dart
index 26ec0447..a658f954 100644
--- a/acceptance_tests/lib/src/steps/step_when_i_subscribe.dart
+++ b/acceptance_tests/lib/src/steps/step_when_i_subscribe.dart
@@ -1,4 +1,3 @@
-import 'dart:convert';
 
 import 'package:gherkin/gherkin.dart';
 
diff --git a/acceptance_tests/pubspec.yaml b/acceptance_tests/pubspec.yaml
index 13758068..fdb35621 100644
--- a/acceptance_tests/pubspec.yaml
+++ b/acceptance_tests/pubspec.yaml
@@ -5,7 +5,7 @@ version: 1.0.0
 publish_to: none
 
 environment:
-  sdk: ">=2.17.0 <3.0.0"
+  sdk: ">=3.0.0 <4.0.0"
 
 dependencies:
   glob: ^2.0.1
diff --git a/pubnub/CHANGELOG.md b/pubnub/CHANGELOG.md
index 69630e83..afd9be1e 100644
--- a/pubnub/CHANGELOG.md
+++ b/pubnub/CHANGELOG.md
@@ -1,3 +1,9 @@
+## v4.2.3
+May 18 2023
+
+#### Fixed
+- Fixes issue of losing timetoken value precision in web environment. Fixed the following issues reported by [@RicharC293](https://github.com/RicharC293): [#110](https://github.com/pubnub/dart/issues/110).
+
 ## v4.2.2
 November 14 2022
 
diff --git a/pubnub/README.md b/pubnub/README.md
index 647a5964..54c4585a 100644
--- a/pubnub/README.md
+++ b/pubnub/README.md
@@ -14,7 +14,7 @@ To add the package to your Dart or Flutter project, add `pubnub` as a dependency
 
 ```yaml
 dependencies:
-  pubnub: ^4.2.2
+  pubnub: ^4.2.3
 ```
 
 After adding the dependency to `pubspec.yaml`, run the `dart pub get` command in the root directory of your project (the same that the `pubspec.yaml` is in).
diff --git a/pubnub/lib/src/core/core.dart b/pubnub/lib/src/core/core.dart
index 377bb99d..c0d0f75b 100644
--- a/pubnub/lib/src/core/core.dart
+++ b/pubnub/lib/src/core/core.dart
@@ -21,7 +21,7 @@ class Core {
   /// Internal module responsible for supervising.
   SupervisorModule supervisor = SupervisorModule();
 
-  static String version = '4.2.2';
+  static String version = '4.2.3';
 
   Core(
       {Keyset? defaultKeyset,
diff --git a/pubnub/lib/src/core/net/exceptions.dart b/pubnub/lib/src/core/net/exceptions.dart
index c5911df3..bfd82a22 100644
--- a/pubnub/lib/src/core/net/exceptions.dart
+++ b/pubnub/lib/src/core/net/exceptions.dart
@@ -2,19 +2,19 @@ import '../exceptions.dart';
 import 'response.dart';
 
 class RequestTimeoutException extends PubNubException {
-  final dynamic? additionalData;
+  final dynamic additionalData;
 
   RequestTimeoutException([this.additionalData]) : super('request timed out');
 }
 
 class RequestCancelException extends PubNubException {
-  final dynamic? additionalData;
+  final dynamic additionalData;
 
   RequestCancelException([this.additionalData]) : super('request cancelled');
 }
 
 class RequestOtherException extends PubNubException {
-  final dynamic? additionalData;
+  final dynamic additionalData;
 
   RequestOtherException([this.additionalData])
       : super('request failed ($additionalData)');
diff --git a/pubnub/lib/src/core/supervisor/signals.dart b/pubnub/lib/src/core/supervisor/signals.dart
index 6e6a3702..de9aab92 100644
--- a/pubnub/lib/src/core/supervisor/signals.dart
+++ b/pubnub/lib/src/core/supervisor/signals.dart
@@ -1,7 +1,6 @@
 import 'dart:async';
 
 import 'package:pubnub/core.dart';
-import 'event.dart';
 
 final _logger = injectLogger('pubnub.core.supervisor.signals');
 
diff --git a/pubnub/lib/src/dx/_endpoints/history.dart b/pubnub/lib/src/dx/_endpoints/history.dart
index 16a7e58b..0c244bae 100644
--- a/pubnub/lib/src/dx/_endpoints/history.dart
+++ b/pubnub/lib/src/dx/_endpoints/history.dart
@@ -65,8 +65,8 @@ class FetchHistoryResult extends Result {
     if (object is List) {
       return FetchHistoryResult._(
           object[0],
-          Timetoken(BigInt.from(object[1] as int)),
-          Timetoken(BigInt.from(object[2] as int)));
+          Timetoken(BigInt.parse('${object[1]}')),
+          Timetoken(BigInt.parse('${object[2]}')));
     }
 
     throw getExceptionFromAny(object);
@@ -161,7 +161,7 @@ class BatchHistoryResultEntry {
         cipherKey == null
             ? object['message']
             : decryptFunction!(cipherKey, object['message']),
-        Timetoken(BigInt.parse(object['timetoken'])),
+        Timetoken(BigInt.parse('${object['timetoken']}')),
         object['uuid'],
         MessageTypeExtension.fromInt(object['message_type']),
         object['actions'],
diff --git a/pubnub/lib/src/dx/_endpoints/objects/membership_metadata.dart b/pubnub/lib/src/dx/_endpoints/objects/membership_metadata.dart
index 1c8b8211..4e300f81 100644
--- a/pubnub/lib/src/dx/_endpoints/objects/membership_metadata.dart
+++ b/pubnub/lib/src/dx/_endpoints/objects/membership_metadata.dart
@@ -59,7 +59,7 @@ class GetMembershipsMetadataParams extends Parameters {
 /// {@category Objects}
 class MembershipMetadata {
   ChannelMetadataDetails _channel;
-  dynamic? _custom;
+  dynamic _custom;
   String _updated;
   String _eTag;
 
@@ -212,12 +212,12 @@ class GetChannelMembersParams extends Parameters {
 /// {@category Objects}
 class ChannelMemberMetadata {
   final UuidMetadataDetails _uuid;
-  final dynamic? _custom;
+  final dynamic _custom;
   final String _updated;
   final String _eTag;
 
   UuidMetadataDetails get uuid => _uuid;
-  dynamic? get custom => _custom;
+  dynamic get custom => _custom;
   String get updated => _updated;
   String get eTag => _eTag;
 
diff --git a/pubnub/lib/src/dx/_endpoints/objects/uuid_metadata.dart b/pubnub/lib/src/dx/_endpoints/objects/uuid_metadata.dart
index f39e5473..f814afe0 100644
--- a/pubnub/lib/src/dx/_endpoints/objects/uuid_metadata.dart
+++ b/pubnub/lib/src/dx/_endpoints/objects/uuid_metadata.dart
@@ -56,7 +56,7 @@ class UuidMetadataDetails {
   String? get externalId => _externalId;
   String? get profileUrl => _profileUrl;
   String? get email => _email;
-  dynamic? get custom => _custom;
+  dynamic get custom => _custom;
   String? get updated => _updated;
   String? get eTag => _eTag;
 
diff --git a/pubnub/lib/src/dx/_utils/exceptions.dart b/pubnub/lib/src/dx/_utils/exceptions.dart
index 602b53af..073eabdf 100644
--- a/pubnub/lib/src/dx/_utils/exceptions.dart
+++ b/pubnub/lib/src/dx/_utils/exceptions.dart
@@ -8,7 +8,7 @@ PubNubException getExceptionFromAny(dynamic error) {
   }
 
   if (error is XmlDocument) {
-    var details = error.rootElement.getElement('Message')?.text;
+    var details = error.rootElement.getElement('Message')?.value;
 
     return PubNubException(
         'Request to third party service failed. Details: $details');
diff --git a/pubnub/lib/src/dx/files/files.dart b/pubnub/lib/src/dx/files/files.dart
index e791547e..5a9f7310 100644
--- a/pubnub/lib/src/dx/files/files.dart
+++ b/pubnub/lib/src/dx/files/files.dart
@@ -54,10 +54,10 @@ class FileDx {
   Future<PublishFileMessageResult> sendFile(
       String channel, String fileName, List<int> file,
       {CipherKey? cipherKey,
-      dynamic? fileMessage,
+      dynamic fileMessage,
       bool? storeFileMessage,
       int? fileMessageTtl,
-      dynamic? fileMessageMeta,
+      dynamic fileMessageMeta,
       Keyset? keyset,
       String? using}) async {
     keyset ??= _core.keysets[using];
@@ -148,7 +148,7 @@ class FileDx {
       String channel, FileMessage message,
       {bool? storeMessage,
       int? ttl,
-      dynamic? meta,
+      dynamic meta,
       CipherKey? cipherKey,
       Keyset? keyset,
       String? using}) async {
diff --git a/pubnub/lib/src/dx/objects/channel_metadata.dart b/pubnub/lib/src/dx/objects/channel_metadata.dart
index 1d17de6e..a3ac63db 100644
--- a/pubnub/lib/src/dx/objects/channel_metadata.dart
+++ b/pubnub/lib/src/dx/objects/channel_metadata.dart
@@ -1,7 +1,5 @@
 import 'package:pubnub/core.dart';
-import '../_endpoints/objects/objects_types.dart';
 import 'objects.dart';
-import 'objects_types.dart';
 
 /// Represents a channel metadata.
 ///
diff --git a/pubnub/lib/src/dx/objects/schema.dart b/pubnub/lib/src/dx/objects/schema.dart
index 5d7a6ec3..b63fc105 100644
--- a/pubnub/lib/src/dx/objects/schema.dart
+++ b/pubnub/lib/src/dx/objects/schema.dart
@@ -4,7 +4,7 @@
 class UuidMetadataInput {
   String? name;
   String? email;
-  dynamic? custom;
+  dynamic custom;
   String? externalId;
   String? profileUrl;
 
@@ -26,7 +26,7 @@ class UuidMetadataInput {
 class ChannelMetadataInput {
   String? name;
   String? description;
-  dynamic? custom;
+  dynamic custom;
 
   ChannelMetadataInput({this.name, this.description, this.custom});
 
diff --git a/pubnub/lib/src/dx/objects/uuid_metadata.dart b/pubnub/lib/src/dx/objects/uuid_metadata.dart
index d978295d..27c9d4ed 100644
--- a/pubnub/lib/src/dx/objects/uuid_metadata.dart
+++ b/pubnub/lib/src/dx/objects/uuid_metadata.dart
@@ -1,7 +1,5 @@
 import 'package:pubnub/core.dart';
-import '../_endpoints/objects/objects_types.dart';
 import 'objects.dart';
-import 'schema.dart';
 
 /// Representation of UuidMetadata object
 /// Useful while dealing with one specific `uuid` details
diff --git a/pubnub/lib/src/dx/time.dart b/pubnub/lib/src/dx/time.dart
index e39d4088..1b50d83b 100644
--- a/pubnub/lib/src/dx/time.dart
+++ b/pubnub/lib/src/dx/time.dart
@@ -9,6 +9,6 @@ mixin TimeDx on Core {
     return defaultFlow<TimeParams, Timetoken>(
         core: this,
         params: TimeParams(),
-        serialize: (object, [_]) => Timetoken(BigInt.from(object[0] as int)));
+        serialize: (object, [_]) => Timetoken(BigInt.parse('${object[0]}')));
   }
 }
diff --git a/pubnub/lib/src/networking/meta/diagnostics/html.dart b/pubnub/lib/src/networking/meta/diagnostics/html.dart
index 997bf86c..9d03e704 100644
--- a/pubnub/lib/src/networking/meta/diagnostics/html.dart
+++ b/pubnub/lib/src/networking/meta/diagnostics/html.dart
@@ -42,4 +42,5 @@ Diagnostic? getNetworkDiagnostic(dynamic exception) {
       return AccessDeniedDiagnostic();
     }
   }
+  return null;
 }
diff --git a/pubnub/lib/src/networking/meta/diagnostics/io.dart b/pubnub/lib/src/networking/meta/diagnostics/io.dart
index 24b1f4c7..d96c6c87 100644
--- a/pubnub/lib/src/networking/meta/diagnostics/io.dart
+++ b/pubnub/lib/src/networking/meta/diagnostics/io.dart
@@ -70,6 +70,7 @@ Diagnostic? getNetworkDiagnostic(dynamic exception) {
       return AccessDeniedDiagnostic();
     }
   }
+  return null;
 }
 
 enum _Errno {
diff --git a/pubnub/lib/src/parser/parser.dart b/pubnub/lib/src/parser/parser.dart
index 3f38a111..518b172a 100644
--- a/pubnub/lib/src/parser/parser.dart
+++ b/pubnub/lib/src/parser/parser.dart
@@ -3,8 +3,6 @@ import 'package:xml/xml.dart' show XmlDocument;
 
 import 'package:pubnub/core.dart';
 
-import '../core/parser.dart';
-
 /// @nodoc
 abstract class Parser<T> {
   Future<T> decode(String input);
diff --git a/pubnub/lib/src/subscribe/envelope.dart b/pubnub/lib/src/subscribe/envelope.dart
index ca10ef72..738d7ed3 100644
--- a/pubnub/lib/src/subscribe/envelope.dart
+++ b/pubnub/lib/src/subscribe/envelope.dart
@@ -1,5 +1,4 @@
 import 'package:pubnub/core.dart';
-import 'package:pubnub/pubnub.dart';
 
 /// Represents a message received from a subscription.
 ///
@@ -17,7 +16,7 @@ class Envelope extends BaseMessage {
   final Timetoken? originalTimetoken;
   final int? originalRegion;
 
-  final dynamic? userMeta;
+  final dynamic userMeta;
 
   dynamic get payload => content;
 
@@ -53,10 +52,10 @@ class Envelope extends BaseMessage {
       flags: object['f'] as int,
       uuid: UUID(object['i'] ?? ''),
       originalTimetoken: object['o'] != null
-          ? Timetoken(BigInt.parse(object['o']['t']))
+          ? Timetoken(BigInt.parse('${object['o']['t']}'))
           : null,
       originalRegion: object['o']?['r'],
-      publishedAt: Timetoken(BigInt.parse(object['p']['t'])),
+      publishedAt: Timetoken(BigInt.parse('${object['p']['t']}')),
       region: object['p']['r'],
       userMeta: object['u'],
     );
diff --git a/pubnub/pubspec.yaml b/pubnub/pubspec.yaml
index 1df49b14..f7d7bd41 100644
--- a/pubnub/pubspec.yaml
+++ b/pubnub/pubspec.yaml
@@ -1,14 +1,14 @@
 name: pubnub
 description: PubNub SDK v5 for Dart lang (with Flutter support) that allows you to create real-time applications
-version: 4.2.2
+version: 4.2.3
 homepage: https://www.pubnub.com/docs/sdks/dart
 
 environment:
-  sdk: ">=2.17.0 <3.0.0"
+  sdk: ">=3.0.0 <4.0.0"
 
 scripts:
   test:
-    default: dart pub run test -P unit
+    default: dart run test -P unit
     integration: dart pub run test -P integration
   validate:
     analysis: dart analyze --fatal-warnings lib
@@ -26,4 +26,4 @@ dependencies:
   pool: ^1.5.0
   xml: ^6.1.0
 dev_dependencies:
-  test: 1.16.7
+  test: ^1.24.3
diff --git a/pubnub/test/integration/subscribe/subscribe_test.dart b/pubnub/test/integration/subscribe/subscribe_test.dart
index e7ebc298..fe22283b 100644
--- a/pubnub/test/integration/subscribe/subscribe_test.dart
+++ b/pubnub/test/integration/subscribe/subscribe_test.dart
@@ -5,7 +5,6 @@ import 'dart:io';
 import 'package:test/test.dart';
 
 import 'package:pubnub/pubnub.dart';
-import 'package:pubnub/core.dart';
 
 import '_utils.dart';
 
diff --git a/pubnub/test/unit/dx/channel_test.dart b/pubnub/test/unit/dx/channel_test.dart
index 68be6655..845c6343 100644
--- a/pubnub/test/unit/dx/channel_test.dart
+++ b/pubnub/test/unit/dx/channel_test.dart
@@ -1,10 +1,6 @@
 import 'package:test/test.dart';
 
 import 'package:pubnub/pubnub.dart';
-import 'package:pubnub/core.dart';
-
-import 'package:pubnub/src/dx/channel/channel.dart';
-import 'package:pubnub/src/dx/channel/channel_history.dart';
 
 import '../net/fake_net.dart';
 part './fixtures/channel.dart';
diff --git a/pubnub/test/unit/dx/file_test.dart b/pubnub/test/unit/dx/file_test.dart
index 8ba8c09f..6523cf3d 100644
--- a/pubnub/test/unit/dx/file_test.dart
+++ b/pubnub/test/unit/dx/file_test.dart
@@ -3,7 +3,6 @@ import 'package:pubnub/crypto.dart';
 import 'package:test/test.dart';
 
 import 'package:pubnub/pubnub.dart';
-import 'package:pubnub/core.dart';
 
 import '../net/fake_net.dart';
 part 'fixtures/files.dart';
diff --git a/pubnub/test/unit/dx/message_action_test.dart b/pubnub/test/unit/dx/message_action_test.dart
index 59eb524b..0e26a9c2 100644
--- a/pubnub/test/unit/dx/message_action_test.dart
+++ b/pubnub/test/unit/dx/message_action_test.dart
@@ -1,9 +1,6 @@
 import 'package:test/test.dart';
 
 import 'package:pubnub/pubnub.dart';
-import 'package:pubnub/core.dart';
-
-import 'package:pubnub/src/dx/_utils/utils.dart';
 
 import '../net/fake_net.dart';
 
diff --git a/pubnub/test/unit/dx/publish_test.dart b/pubnub/test/unit/dx/publish_test.dart
index 968d16af..4d2df118 100644
--- a/pubnub/test/unit/dx/publish_test.dart
+++ b/pubnub/test/unit/dx/publish_test.dart
@@ -1,8 +1,6 @@
 import 'package:test/test.dart';
 
 import 'package:pubnub/pubnub.dart';
-import 'package:pubnub/core.dart';
-import 'package:pubnub/src/dx/_utils/utils.dart';
 
 import '../net/fake_net.dart';
 part './fixtures/publish.dart';
diff --git a/pubnub/test/unit/dx/push_test.dart b/pubnub/test/unit/dx/push_test.dart
index 35ae0989..c090ac18 100644
--- a/pubnub/test/unit/dx/push_test.dart
+++ b/pubnub/test/unit/dx/push_test.dart
@@ -1,9 +1,6 @@
 import 'package:test/test.dart';
 
 import 'package:pubnub/pubnub.dart';
-import 'package:pubnub/core.dart';
-import 'package:pubnub/src/dx/_endpoints/push.dart';
-import 'package:pubnub/src/dx/_utils/utils.dart';
 
 import '../net/fake_net.dart';
 part './fixtures/push.dart';
diff --git a/pubnub/test/unit/net/utils.dart b/pubnub/test/unit/net/utils.dart
index 308c7be9..039ca63a 100644
--- a/pubnub/test/unit/net/utils.dart
+++ b/pubnub/test/unit/net/utils.dart
@@ -8,13 +8,16 @@ void main() {
       expect(isHeaderForbidden('Content-Length'), equals(true));
     });
 
-    test('isHeaderForbidden should return true for any Sec- or Proxy- header', () {
+    test('isHeaderForbidden should return true for any Sec- or Proxy- header',
+        () {
       expect(isHeaderForbidden('Sec-Test-1'), equals(true));
       expect(isHeaderForbidden('Sec-Random-2'), equals(true));
       expect(isHeaderForbidden('Proxy-Whatever'), equals(true));
     });
 
-    test('isHeaderForbidden should return false for any other header not specified', () {
+    test(
+        'isHeaderForbidden should return false for any other header not specified',
+        () {
       expect(isHeaderForbidden('X-Custom-Header'), equals(false));
       expect(isHeaderForbidden('Content-Type'), equals(false));
     });