diff --git a/.github/workflows/dart.yml b/.github/workflows/dart.yml
index bd81c5a2..e2bd9d6d 100644
--- a/.github/workflows/dart.yml
+++ b/.github/workflows/dart.yml
@@ -40,23 +40,23 @@ jobs:
       - name: mono_repo self validate
         run: dart pub global run mono_repo generate --validate
   job_002:
-    name: "analyze_and_format; linux; Dart 3.0.0; PKGS: pkgs/shelf, pkgs/shelf_packages_handler, pkgs/shelf_proxy, pkgs/shelf_router, pkgs/shelf_router_generator, pkgs/shelf_static, pkgs/shelf_test_handler, pkgs/shelf_web_socket; `dart analyze --fatal-infos .`"
+    name: "analyze_and_format; linux; Dart 3.3.0; PKGS: pkgs/shelf, pkgs/shelf_packages_handler, pkgs/shelf_proxy, pkgs/shelf_router, pkgs/shelf_router_generator, pkgs/shelf_static, pkgs/shelf_test_handler, pkgs/shelf_web_socket; `dart analyze --fatal-infos .`"
     runs-on: ubuntu-latest
     steps:
       - name: Cache Pub hosted dependencies
         uses: actions/cache@0c45773b623bea8c8e75f6c82b208c3cf94ea4f9
         with:
           path: "~/.pub-cache/hosted"
-          key: "os:ubuntu-latest;pub-cache-hosted;sdk:3.0.0;packages:pkgs/shelf-pkgs/shelf_packages_handler-pkgs/shelf_proxy-pkgs/shelf_router-pkgs/shelf_router_generator-pkgs/shelf_static-pkgs/shelf_test_handler-pkgs/shelf_web_socket;commands:analyze"
+          key: "os:ubuntu-latest;pub-cache-hosted;sdk:3.3.0;packages:pkgs/shelf-pkgs/shelf_packages_handler-pkgs/shelf_proxy-pkgs/shelf_router-pkgs/shelf_router_generator-pkgs/shelf_static-pkgs/shelf_test_handler-pkgs/shelf_web_socket;commands:analyze"
           restore-keys: |
-            os:ubuntu-latest;pub-cache-hosted;sdk:3.0.0;packages:pkgs/shelf-pkgs/shelf_packages_handler-pkgs/shelf_proxy-pkgs/shelf_router-pkgs/shelf_router_generator-pkgs/shelf_static-pkgs/shelf_test_handler-pkgs/shelf_web_socket
-            os:ubuntu-latest;pub-cache-hosted;sdk:3.0.0
+            os:ubuntu-latest;pub-cache-hosted;sdk:3.3.0;packages:pkgs/shelf-pkgs/shelf_packages_handler-pkgs/shelf_proxy-pkgs/shelf_router-pkgs/shelf_router_generator-pkgs/shelf_static-pkgs/shelf_test_handler-pkgs/shelf_web_socket
+            os:ubuntu-latest;pub-cache-hosted;sdk:3.3.0
             os:ubuntu-latest;pub-cache-hosted
             os:ubuntu-latest
       - name: Setup Dart SDK
         uses: dart-lang/setup-dart@f0ead981b4d9a35b37f30d36160575d60931ec30
         with:
-          sdk: "3.0.0"
+          sdk: "3.3.0"
       - id: checkout
         name: Checkout repository
         uses: actions/checkout@44c2b7a8a4ea60a981eaca3cf939b5f4305c123b
@@ -319,23 +319,23 @@ jobs:
         if: "always() && steps.pkgs_shelf_web_socket_pub_upgrade.conclusion == 'success'"
         working-directory: pkgs/shelf_web_socket
   job_005:
-    name: "unit_test; linux; Dart 3.0.0; PKGS: pkgs/shelf, pkgs/shelf_test_handler; `dart test --test-randomize-ordering-seed=random -p chrome`"
+    name: "unit_test; linux; Dart 3.3.0; PKGS: pkgs/shelf, pkgs/shelf_test_handler; `dart test --test-randomize-ordering-seed=random -p chrome`"
     runs-on: ubuntu-latest
     steps:
       - name: Cache Pub hosted dependencies
         uses: actions/cache@0c45773b623bea8c8e75f6c82b208c3cf94ea4f9
         with:
           path: "~/.pub-cache/hosted"
-          key: "os:ubuntu-latest;pub-cache-hosted;sdk:3.0.0;packages:pkgs/shelf-pkgs/shelf_test_handler;commands:test_1"
+          key: "os:ubuntu-latest;pub-cache-hosted;sdk:3.3.0;packages:pkgs/shelf-pkgs/shelf_test_handler;commands:test_1"
           restore-keys: |
-            os:ubuntu-latest;pub-cache-hosted;sdk:3.0.0;packages:pkgs/shelf-pkgs/shelf_test_handler
-            os:ubuntu-latest;pub-cache-hosted;sdk:3.0.0
+            os:ubuntu-latest;pub-cache-hosted;sdk:3.3.0;packages:pkgs/shelf-pkgs/shelf_test_handler
+            os:ubuntu-latest;pub-cache-hosted;sdk:3.3.0
             os:ubuntu-latest;pub-cache-hosted
             os:ubuntu-latest
       - name: Setup Dart SDK
         uses: dart-lang/setup-dart@f0ead981b4d9a35b37f30d36160575d60931ec30
         with:
-          sdk: "3.0.0"
+          sdk: "3.3.0"
       - id: checkout
         name: Checkout repository
         uses: actions/checkout@44c2b7a8a4ea60a981eaca3cf939b5f4305c123b
@@ -363,23 +363,23 @@ jobs:
       - job_003
       - job_004
   job_006:
-    name: "unit_test; linux; Dart 3.0.0; PKGS: pkgs/shelf, pkgs/shelf_packages_handler, pkgs/shelf_proxy, pkgs/shelf_router, pkgs/shelf_router_generator, pkgs/shelf_static, pkgs/shelf_test_handler, pkgs/shelf_web_socket; `dart test --test-randomize-ordering-seed=random`"
+    name: "unit_test; linux; Dart 3.3.0; PKGS: pkgs/shelf, pkgs/shelf_packages_handler, pkgs/shelf_proxy, pkgs/shelf_router, pkgs/shelf_router_generator, pkgs/shelf_static, pkgs/shelf_test_handler, pkgs/shelf_web_socket; `dart test --test-randomize-ordering-seed=random`"
     runs-on: ubuntu-latest
     steps:
       - name: Cache Pub hosted dependencies
         uses: actions/cache@0c45773b623bea8c8e75f6c82b208c3cf94ea4f9
         with:
           path: "~/.pub-cache/hosted"
-          key: "os:ubuntu-latest;pub-cache-hosted;sdk:3.0.0;packages:pkgs/shelf-pkgs/shelf_packages_handler-pkgs/shelf_proxy-pkgs/shelf_router-pkgs/shelf_router_generator-pkgs/shelf_static-pkgs/shelf_test_handler-pkgs/shelf_web_socket;commands:test_0"
+          key: "os:ubuntu-latest;pub-cache-hosted;sdk:3.3.0;packages:pkgs/shelf-pkgs/shelf_packages_handler-pkgs/shelf_proxy-pkgs/shelf_router-pkgs/shelf_router_generator-pkgs/shelf_static-pkgs/shelf_test_handler-pkgs/shelf_web_socket;commands:test_0"
           restore-keys: |
-            os:ubuntu-latest;pub-cache-hosted;sdk:3.0.0;packages:pkgs/shelf-pkgs/shelf_packages_handler-pkgs/shelf_proxy-pkgs/shelf_router-pkgs/shelf_router_generator-pkgs/shelf_static-pkgs/shelf_test_handler-pkgs/shelf_web_socket
-            os:ubuntu-latest;pub-cache-hosted;sdk:3.0.0
+            os:ubuntu-latest;pub-cache-hosted;sdk:3.3.0;packages:pkgs/shelf-pkgs/shelf_packages_handler-pkgs/shelf_proxy-pkgs/shelf_router-pkgs/shelf_router_generator-pkgs/shelf_static-pkgs/shelf_test_handler-pkgs/shelf_web_socket
+            os:ubuntu-latest;pub-cache-hosted;sdk:3.3.0
             os:ubuntu-latest;pub-cache-hosted
             os:ubuntu-latest
       - name: Setup Dart SDK
         uses: dart-lang/setup-dart@f0ead981b4d9a35b37f30d36160575d60931ec30
         with:
-          sdk: "3.0.0"
+          sdk: "3.3.0"
       - id: checkout
         name: Checkout repository
         uses: actions/checkout@44c2b7a8a4ea60a981eaca3cf939b5f4305c123b
@@ -682,13 +682,13 @@ jobs:
       - job_003
       - job_004
   job_011:
-    name: "unit_test; windows; Dart 3.0.0; PKGS: pkgs/shelf, pkgs/shelf_test_handler; `dart test --test-randomize-ordering-seed=random -p chrome`"
+    name: "unit_test; windows; Dart 3.3.0; PKGS: pkgs/shelf, pkgs/shelf_test_handler; `dart test --test-randomize-ordering-seed=random -p chrome`"
     runs-on: windows-latest
     steps:
       - name: Setup Dart SDK
         uses: dart-lang/setup-dart@f0ead981b4d9a35b37f30d36160575d60931ec30
         with:
-          sdk: "3.0.0"
+          sdk: "3.3.0"
       - id: checkout
         name: Checkout repository
         uses: actions/checkout@44c2b7a8a4ea60a981eaca3cf939b5f4305c123b
@@ -716,13 +716,13 @@ jobs:
       - job_003
       - job_004
   job_012:
-    name: "unit_test; windows; Dart 3.0.0; PKGS: pkgs/shelf_packages_handler, pkgs/shelf_static, pkgs/shelf_test_handler, pkgs/shelf_web_socket; `dart test --test-randomize-ordering-seed=random`"
+    name: "unit_test; windows; Dart 3.3.0; PKGS: pkgs/shelf_packages_handler, pkgs/shelf_static, pkgs/shelf_test_handler, pkgs/shelf_web_socket; `dart test --test-randomize-ordering-seed=random`"
     runs-on: windows-latest
     steps:
       - name: Setup Dart SDK
         uses: dart-lang/setup-dart@f0ead981b4d9a35b37f30d36160575d60931ec30
         with:
-          sdk: "3.0.0"
+          sdk: "3.3.0"
       - id: checkout
         name: Checkout repository
         uses: actions/checkout@44c2b7a8a4ea60a981eaca3cf939b5f4305c123b
diff --git a/pkgs/shelf/CHANGELOG.md b/pkgs/shelf/CHANGELOG.md
index e8ef847e..abd27324 100644
--- a/pkgs/shelf/CHANGELOG.md
+++ b/pkgs/shelf/CHANGELOG.md
@@ -1,6 +1,6 @@
 ## 1.4.2-wip
 
-* Require Dart ^3.0.0
+* Require Dart `^3.3.0`.
 
 ## 1.4.1
 
diff --git a/pkgs/shelf/lib/src/cascade.dart b/pkgs/shelf/lib/src/cascade.dart
index 577c5067..992aea6e 100644
--- a/pkgs/shelf/lib/src/cascade.dart
+++ b/pkgs/shelf/lib/src/cascade.dart
@@ -73,7 +73,7 @@ class Cascade {
 
     return (request) {
       if (_parent!._handler == null) return handler(request);
-      return Future.sync(() => _parent!.handler(request)).then((response) {
+      return Future.sync(() => _parent.handler(request)).then((response) {
         if (_shouldCascade(response)) return handler(request);
         return response;
       });
diff --git a/pkgs/shelf/lib/src/request.dart b/pkgs/shelf/lib/src/request.dart
index bf77f49f..7be8b3ff 100644
--- a/pkgs/shelf/lib/src/request.dart
+++ b/pkgs/shelf/lib/src/request.dart
@@ -60,7 +60,7 @@ class Request extends Message {
   ///
   /// This will be `false` either if the adapter doesn't support hijacking, or
   /// if the request has already been hijacked.
-  bool get canHijack => _onHijack != null && !_onHijack!.called;
+  bool get canHijack => _onHijack != null && !_onHijack.called;
 
   /// If this is non-`null` and the requested resource hasn't been modified
   /// since this date and time, the server should return a 304 Not Modified
@@ -280,7 +280,7 @@ class Request extends Message {
       throw StateError("This request can't be hijacked.");
     }
 
-    _onHijack!.run(callback);
+    _onHijack.run(callback);
 
     throw const HijackException();
   }
diff --git a/pkgs/shelf/lib/src/server_handler.dart b/pkgs/shelf/lib/src/server_handler.dart
index 1dd968bd..a25cdf0c 100644
--- a/pkgs/shelf/lib/src/server_handler.dart
+++ b/pkgs/shelf/lib/src/server_handler.dart
@@ -89,7 +89,7 @@ class _HandlerServer implements Server {
 
   @override
   Future<void> close() => _closeMemo.runOnce(() {
-        return _onClose == null ? null : _onClose!();
+        return _onClose == null ? null : _onClose();
       });
   final _closeMemo = AsyncMemoizer<void>();
 }
diff --git a/pkgs/shelf/pubspec.yaml b/pkgs/shelf/pubspec.yaml
index 72be310f..11f8671b 100644
--- a/pkgs/shelf/pubspec.yaml
+++ b/pkgs/shelf/pubspec.yaml
@@ -10,7 +10,7 @@ topics:
   - backend
 
 environment:
-  sdk: ^3.0.0
+  sdk: ^3.3.0
 
 dependencies:
   async: ^2.5.0
@@ -21,6 +21,6 @@ dependencies:
   stream_channel: ^2.1.0
 
 dev_dependencies:
-  dart_flutter_team_lints: ^2.0.0
+  dart_flutter_team_lints: ^3.0.0
   http: '>=0.13.0 <2.0.0'
   test: ^1.16.0
diff --git a/pkgs/shelf_packages_handler/CHANGELOG.md b/pkgs/shelf_packages_handler/CHANGELOG.md
index 2f6ce796..ade77478 100644
--- a/pkgs/shelf_packages_handler/CHANGELOG.md
+++ b/pkgs/shelf_packages_handler/CHANGELOG.md
@@ -1,6 +1,6 @@
 ## 3.0.3-wip
 
-* Require Dart `^3.0.0`
+* Require Dart `^3.3.0`.
 
 ## 3.0.2
 
diff --git a/pkgs/shelf_packages_handler/lib/src/package_config_handler.dart b/pkgs/shelf_packages_handler/lib/src/package_config_handler.dart
index 460885fa..2ffb091f 100644
--- a/pkgs/shelf_packages_handler/lib/src/package_config_handler.dart
+++ b/pkgs/shelf_packages_handler/lib/src/package_config_handler.dart
@@ -36,7 +36,7 @@ class PackageConfigHandler {
       _packageHandlers.putIfAbsent(packageName, () async {
         Uri? packageUri;
         if (_packageMap != null) {
-          packageUri = _packageMap![packageName];
+          packageUri = _packageMap[packageName];
         } else {
           final fakeResolvedUri = await Isolate.resolvePackageUri(
               Uri(scheme: 'package', path: '$packageName/'));
diff --git a/pkgs/shelf_packages_handler/pubspec.yaml b/pkgs/shelf_packages_handler/pubspec.yaml
index 3c04d3f7..bd119031 100644
--- a/pkgs/shelf_packages_handler/pubspec.yaml
+++ b/pkgs/shelf_packages_handler/pubspec.yaml
@@ -8,7 +8,7 @@ topics:
   - shelf
 
 environment:
-  sdk: ^3.0.0
+  sdk: ^3.3.0
 
 dependencies:
   path: ^1.8.0
@@ -16,5 +16,5 @@ dependencies:
   shelf_static: ^1.0.0
 
 dev_dependencies:
-  dart_flutter_team_lints: ^2.0.0
+  dart_flutter_team_lints: ^3.0.0
   test: ^1.16.0
diff --git a/pkgs/shelf_proxy/CHANGELOG.md b/pkgs/shelf_proxy/CHANGELOG.md
index 07041940..17363646 100644
--- a/pkgs/shelf_proxy/CHANGELOG.md
+++ b/pkgs/shelf_proxy/CHANGELOG.md
@@ -1,6 +1,6 @@
 ## 1.0.5-wip
 
-* Require Dart `^3.0.0`
+* Require Dart `^3.3.0`.
 
 ## 1.0.4
 
diff --git a/pkgs/shelf_proxy/pubspec.yaml b/pkgs/shelf_proxy/pubspec.yaml
index e8c3c2aa..1ac4060d 100644
--- a/pkgs/shelf_proxy/pubspec.yaml
+++ b/pkgs/shelf_proxy/pubspec.yaml
@@ -8,7 +8,7 @@ topics:
   - shelf
 
 environment:
-  sdk: ^3.0.0
+  sdk: ^3.3.0
 
 dependencies:
   http: '>=0.13.0 <2.0.0'
@@ -16,5 +16,5 @@ dependencies:
   shelf: ^1.0.0
 
 dev_dependencies:
-  dart_flutter_team_lints: ^2.0.0
+  dart_flutter_team_lints: ^3.0.0
   test: ^1.6.0
diff --git a/pkgs/shelf_router/CHANGELOG.md b/pkgs/shelf_router/CHANGELOG.md
index c3dbf816..6e88703e 100644
--- a/pkgs/shelf_router/CHANGELOG.md
+++ b/pkgs/shelf_router/CHANGELOG.md
@@ -1,6 +1,6 @@
 ## 1.1.5-wip
 
-* Require Dart `^3.0.0`.
+* Require Dart `^3.3.0`.
 
 ## 1.1.4
 
diff --git a/pkgs/shelf_router/lib/shelf_router.dart b/pkgs/shelf_router/lib/shelf_router.dart
index fb4c63f8..c6ec482c 100644
--- a/pkgs/shelf_router/lib/shelf_router.dart
+++ b/pkgs/shelf_router/lib/shelf_router.dart
@@ -76,7 +76,7 @@
 ///   await io.serve(service.router.handler, 'localhost', 8080);
 /// }
 /// ```
-library shelf_router;
+library;
 
 import 'src/route.dart';
 import 'src/router.dart';
diff --git a/pkgs/shelf_router/pubspec.yaml b/pkgs/shelf_router/pubspec.yaml
index b2eed2c5..9be8a34f 100644
--- a/pkgs/shelf_router/pubspec.yaml
+++ b/pkgs/shelf_router/pubspec.yaml
@@ -10,7 +10,7 @@ topics:
   - shelf
 
 environment:
-  sdk: ^3.0.0
+  sdk: ^3.3.0
 
 dependencies:
   http_methods: ^1.1.0
@@ -18,6 +18,6 @@ dependencies:
   shelf: ^1.0.0
 
 dev_dependencies:
-  dart_flutter_team_lints: ^2.0.0
+  dart_flutter_team_lints: ^3.0.0
   http: '>=0.13.0 <2.0.0'
   test: ^1.16.0
diff --git a/pkgs/shelf_router_generator/CHANGELOG.md b/pkgs/shelf_router_generator/CHANGELOG.md
index 6a03aff1..eeac453c 100644
--- a/pkgs/shelf_router_generator/CHANGELOG.md
+++ b/pkgs/shelf_router_generator/CHANGELOG.md
@@ -1,3 +1,7 @@
+## 1.1.1-wip
+
+* Require `sdk: ^3.3.0`
+
 ## 1.1.0
 
 * Require `sdk: ^3.0.0`
diff --git a/pkgs/shelf_router_generator/lib/builder.dart b/pkgs/shelf_router_generator/lib/builder.dart
index 4430571b..5fe106a2 100644
--- a/pkgs/shelf_router_generator/lib/builder.dart
+++ b/pkgs/shelf_router_generator/lib/builder.dart
@@ -18,7 +18,7 @@
 /// This is **not intended** for consumption, this library should be used by
 /// running `pub run build_runner build`. Using this library through other means
 /// is not supported and may break arbitrarily.
-library builder;
+library;
 
 import 'package:build/build.dart';
 import 'package:shelf_router/shelf_router.dart' as shelf_router;
diff --git a/pkgs/shelf_router_generator/pubspec.yaml b/pkgs/shelf_router_generator/pubspec.yaml
index 11453c8a..1dfc6832 100644
--- a/pkgs/shelf_router_generator/pubspec.yaml
+++ b/pkgs/shelf_router_generator/pubspec.yaml
@@ -1,5 +1,5 @@
 name: shelf_router_generator
-version: 1.1.0
+version: 1.1.1-wip
 description: >
   A package:build-compatible builder for generating request routers for the
   shelf web-framework based on source annotations.
@@ -10,7 +10,7 @@ topics:
   - shelf
 
 environment:
-  sdk: ^3.0.0
+  sdk: ^3.3.0
 
 dependencies:
   analyzer: '>=4.6.0 <7.0.0'
@@ -25,6 +25,6 @@ dependencies:
 dev_dependencies:
   build_runner: ^2.0.0
   build_verify: ^3.0.0
-  dart_flutter_team_lints: ^2.0.0
+  dart_flutter_team_lints: ^3.0.0
   http: '>=0.13.0 <2.0.0'
   test: ^1.5.3
diff --git a/pkgs/shelf_static/CHANGELOG.md b/pkgs/shelf_static/CHANGELOG.md
index 496c589b..7713e435 100644
--- a/pkgs/shelf_static/CHANGELOG.md
+++ b/pkgs/shelf_static/CHANGELOG.md
@@ -1,6 +1,6 @@
 ## 1.1.3-wip
 
-* Require Dart `^3.0.0`.
+* Require Dart `^3.3.0`.
 
 ## 1.1.2
 
diff --git a/pkgs/shelf_static/pubspec.yaml b/pkgs/shelf_static/pubspec.yaml
index 14b15dc9..4c3a6723 100644
--- a/pkgs/shelf_static/pubspec.yaml
+++ b/pkgs/shelf_static/pubspec.yaml
@@ -8,7 +8,7 @@ topics:
   - shelf
 
 environment:
-  sdk: ^3.0.0
+  sdk: ^3.3.0
 
 dependencies:
   convert: ^3.0.0
@@ -20,6 +20,6 @@ dependencies:
 
 dev_dependencies:
   args: ^2.0.0
-  dart_flutter_team_lints: ^2.0.0
+  dart_flutter_team_lints: ^3.0.0
   test: ^1.16.0
   test_descriptor: ^2.0.0
diff --git a/pkgs/shelf_test_handler/CHANGELOG.md b/pkgs/shelf_test_handler/CHANGELOG.md
index 56b4e792..941ecbc6 100644
--- a/pkgs/shelf_test_handler/CHANGELOG.md
+++ b/pkgs/shelf_test_handler/CHANGELOG.md
@@ -1,6 +1,6 @@
 ## 2.0.3-wip
 
-* Require Dart `^3.0.0`.
+* Require Dart `^3.3.0`.
 
 ## 2.0.2
 
diff --git a/pkgs/shelf_test_handler/pubspec.yaml b/pkgs/shelf_test_handler/pubspec.yaml
index 0b77af4c..fe0238e6 100644
--- a/pkgs/shelf_test_handler/pubspec.yaml
+++ b/pkgs/shelf_test_handler/pubspec.yaml
@@ -8,7 +8,7 @@ topics:
   - shelf
 
 environment:
-  sdk: ^3.0.0
+  sdk: ^3.3.0
 
 dependencies:
   http_multi_server: ^3.0.0
@@ -16,7 +16,7 @@ dependencies:
   test: ^1.16.0
 
 dev_dependencies:
-  dart_flutter_team_lints: ^2.0.0
+  dart_flutter_team_lints: ^3.0.0
   http: '>=0.13.0 <2.0.0'
   shelf_web_socket: ^1.0.0
   web_socket_channel: ^2.0.0
diff --git a/pkgs/shelf_web_socket/CHANGELOG.md b/pkgs/shelf_web_socket/CHANGELOG.md
index a9300190..77f0882d 100644
--- a/pkgs/shelf_web_socket/CHANGELOG.md
+++ b/pkgs/shelf_web_socket/CHANGELOG.md
@@ -1,5 +1,7 @@
 ## 2.0.1-wip
 
+* Require Dart `^3.3.0`.
+
 ## 2.0.0
 
 * Require Dart `^3.0.0`.
diff --git a/pkgs/shelf_web_socket/lib/src/web_socket_handler.dart b/pkgs/shelf_web_socket/lib/src/web_socket_handler.dart
index a41ed697..4c9c5ceb 100644
--- a/pkgs/shelf_web_socket/lib/src/web_socket_handler.dart
+++ b/pkgs/shelf_web_socket/lib/src/web_socket_handler.dart
@@ -66,7 +66,7 @@ class WebSocketHandler {
     final origin = request.headers['Origin'];
     if (origin != null &&
         _allowedOrigins != null &&
-        !_allowedOrigins!.contains(origin.toLowerCase())) {
+        !_allowedOrigins.contains(origin.toLowerCase())) {
       return _forbidden('invalid origin "$origin".');
     }
 
@@ -102,7 +102,7 @@ class WebSocketHandler {
     if (_protocols == null) return null;
     for (var requestProtocol in requestProtocols.split(',')) {
       requestProtocol = requestProtocol.trim();
-      if (_protocols!.contains(requestProtocol)) return requestProtocol;
+      if (_protocols.contains(requestProtocol)) return requestProtocol;
     }
     return null;
   }
diff --git a/pkgs/shelf_web_socket/pubspec.yaml b/pkgs/shelf_web_socket/pubspec.yaml
index 14c92967..84cf9f2f 100644
--- a/pkgs/shelf_web_socket/pubspec.yaml
+++ b/pkgs/shelf_web_socket/pubspec.yaml
@@ -9,7 +9,7 @@ topics:
   - shelf
 
 environment:
-  sdk: ^3.0.0
+  sdk: ^3.3.0
 
 dependencies:
   shelf: ^1.1.0
@@ -17,6 +17,6 @@ dependencies:
   web_socket_channel: '>=2.0.0 <4.0.0'
 
 dev_dependencies:
-  dart_flutter_team_lints: ^2.0.0
+  dart_flutter_team_lints: ^3.0.0
   http: '>=0.13.0 <2.0.0'
   test: ^1.25.2