diff --git a/dev/devicelab/bin/tasks/flutter_attach_test_fuchsia.dart b/dev/devicelab/bin/tasks/flutter_attach_test_fuchsia.dart
index 6d388e7800..016f8f047e 100644
--- a/dev/devicelab/bin/tasks/flutter_attach_test_fuchsia.dart
+++ b/dev/devicelab/bin/tasks/flutter_attach_test_fuchsia.dart
@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-// @dart = 2.8
-
 import 'dart:async';
 import 'dart:convert';
 import 'dart:io';
@@ -116,8 +114,8 @@ void main() {
         'sentinel-${random.nextInt(1<<32)}': Completer<void>(),
       };
 
-      Process runProcess;
-      Process logsProcess;
+      late Process runProcess;
+      late Process logsProcess;
 
       try {
         section('Creating lib/fuchsia_main.dart');
@@ -158,12 +156,12 @@ void main() {
             print('logs:stdout: $log');
             for (final String sentinel in sentinelMessage.keys) {
               if (log.contains(sentinel)) {
-                if (sentinelMessage[sentinel].isCompleted) {
+                if (sentinelMessage[sentinel]!.isCompleted) {
                   throw Exception(
                     'Expected a single `$sentinel` message in the device log, but found more than one'
                   );
                 }
-                sentinelMessage[sentinel].complete();
+                sentinelMessage[sentinel]!.complete();
                 break;
               }
             }
@@ -230,7 +228,7 @@ void main() {
       }
 
       for (final String sentinel in sentinelMessage.keys) {
-        if (!sentinelMessage[sentinel].isCompleted) {
+        if (!sentinelMessage[sentinel]!.isCompleted) {
           throw Exception('Expected $sentinel in the device logs.');
         }
       }
diff --git a/dev/devicelab/bin/tasks/flutter_engine_group_performance.dart b/dev/devicelab/bin/tasks/flutter_engine_group_performance.dart
index f85cbf9177..63beff9861 100644
--- a/dev/devicelab/bin/tasks/flutter_engine_group_performance.dart
+++ b/dev/devicelab/bin/tasks/flutter_engine_group_performance.dart
@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-// @dart = 2.8
-
 import 'dart:io';
 
 import 'package:flutter_devicelab/framework/devices.dart';
@@ -73,7 +71,7 @@ Future<TaskResult> _doTest() async {
     final String apkPath = path.join(multipleFluttersPath, 'android', 'app',
         'build', 'outputs', 'apk', 'release', 'app-release.apk');
 
-    TaskResult result;
+    TaskResult? result;
     await _withApkInstall(apkPath, _bundleName, (AndroidDevice device) async {
       final List<int> totalMemorySamples = <int>[];
       for (int i = 0; i < _numberOfIterations; ++i) {
diff --git a/dev/devicelab/bin/tasks/flutter_gallery__back_button_memory.dart b/dev/devicelab/bin/tasks/flutter_gallery__back_button_memory.dart
index 83401c256d..d14c90e3c6 100644
--- a/dev/devicelab/bin/tasks/flutter_gallery__back_button_memory.dart
+++ b/dev/devicelab/bin/tasks/flutter_gallery__back_button_memory.dart
@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-// @dart = 2.8
-
 /// Measure application memory usage after pausing and resuming the app
 /// with the Android back button.
 
@@ -19,7 +17,7 @@ class BackButtonMemoryTest extends MemoryTest {
   BackButtonMemoryTest() : super('${flutterDirectory.path}/dev/integration_tests/flutter_gallery', 'test_memory/back_button.dart', packageName);
 
   @override
-  AndroidDevice get device => super.device as AndroidDevice;
+  AndroidDevice? get device => super.device as AndroidDevice?;
 
   @override
   int get iterationCount => 5;
@@ -34,7 +32,7 @@ class BackButtonMemoryTest extends MemoryTest {
 
       // Push back button, wait for it to be seen by the Flutter app.
       prepareForNextMessage('AppLifecycleState.paused');
-      await device.shellExec('input', <String>['keyevent', 'KEYCODE_BACK']);
+      await device!.shellExec('input', <String>['keyevent', 'KEYCODE_BACK']);
       await receivedNextMessage;
 
       // Give Android time to settle (e.g. run GCs) after closing the app.
@@ -42,7 +40,7 @@ class BackButtonMemoryTest extends MemoryTest {
 
       // Relaunch the app, wait for it to launch.
       prepareForNextMessage('READY');
-      final String output = await device.shellEval('am', <String>['start', '-n', '$packageName/$activityName']);
+      final String output = await device!.shellEval('am', <String>['start', '-n', '$packageName/$activityName']);
       print('adb shell am start: $output');
       if (output.contains('Error'))
         fail('unable to launch activity');
diff --git a/dev/devicelab/bin/tasks/flutter_gallery__image_cache_memory.dart b/dev/devicelab/bin/tasks/flutter_gallery__image_cache_memory.dart
index f3bcdae07e..52cd208490 100644
--- a/dev/devicelab/bin/tasks/flutter_gallery__image_cache_memory.dart
+++ b/dev/devicelab/bin/tasks/flutter_gallery__image_cache_memory.dart
@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-// @dart = 2.8
-
 import 'package:flutter_devicelab/framework/framework.dart';
 import 'package:flutter_devicelab/framework/utils.dart';
 import 'package:flutter_devicelab/tasks/perf_tests.dart';
diff --git a/dev/devicelab/bin/tasks/flutter_gallery__memory_nav.dart b/dev/devicelab/bin/tasks/flutter_gallery__memory_nav.dart
index 128b0d61ea..3b83a78bb8 100644
--- a/dev/devicelab/bin/tasks/flutter_gallery__memory_nav.dart
+++ b/dev/devicelab/bin/tasks/flutter_gallery__memory_nav.dart
@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-// @dart = 2.8
-
 import 'package:flutter_devicelab/framework/framework.dart';
 import 'package:flutter_devicelab/framework/utils.dart';
 import 'package:flutter_devicelab/tasks/perf_tests.dart';
diff --git a/dev/devicelab/bin/tasks/flutter_gallery__start_up.dart b/dev/devicelab/bin/tasks/flutter_gallery__start_up.dart
index 2bdec9435d..e84cf5311b 100644
--- a/dev/devicelab/bin/tasks/flutter_gallery__start_up.dart
+++ b/dev/devicelab/bin/tasks/flutter_gallery__start_up.dart
@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-// @dart = 2.8
-
 import 'package:flutter_devicelab/framework/devices.dart';
 import 'package:flutter_devicelab/framework/framework.dart';
 import 'package:flutter_devicelab/tasks/perf_tests.dart';
diff --git a/dev/devicelab/bin/tasks/flutter_gallery__transition_perf.dart b/dev/devicelab/bin/tasks/flutter_gallery__transition_perf.dart
index 94f2ced349..dde9d8c3d6 100644
--- a/dev/devicelab/bin/tasks/flutter_gallery__transition_perf.dart
+++ b/dev/devicelab/bin/tasks/flutter_gallery__transition_perf.dart
@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-// @dart = 2.8
-
 import 'package:flutter_devicelab/framework/devices.dart';
 import 'package:flutter_devicelab/framework/framework.dart';
 import 'package:flutter_devicelab/tasks/gallery.dart';
diff --git a/dev/devicelab/bin/tasks/flutter_gallery__transition_perf_e2e.dart b/dev/devicelab/bin/tasks/flutter_gallery__transition_perf_e2e.dart
index 7f8bd7db64..8a66049914 100644
--- a/dev/devicelab/bin/tasks/flutter_gallery__transition_perf_e2e.dart
+++ b/dev/devicelab/bin/tasks/flutter_gallery__transition_perf_e2e.dart
@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-// @dart = 2.8
-
 import 'package:flutter_devicelab/framework/devices.dart';
 import 'package:flutter_devicelab/framework/framework.dart';
 import 'package:flutter_devicelab/tasks/gallery.dart';
diff --git a/dev/devicelab/bin/tasks/flutter_gallery__transition_perf_e2e_ios.dart b/dev/devicelab/bin/tasks/flutter_gallery__transition_perf_e2e_ios.dart
index 88d6b3f2ff..4792368b91 100644
--- a/dev/devicelab/bin/tasks/flutter_gallery__transition_perf_e2e_ios.dart
+++ b/dev/devicelab/bin/tasks/flutter_gallery__transition_perf_e2e_ios.dart
@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-// @dart = 2.8
-
 import 'package:flutter_devicelab/framework/devices.dart';
 import 'package:flutter_devicelab/framework/framework.dart';
 import 'package:flutter_devicelab/tasks/gallery.dart';
diff --git a/dev/devicelab/bin/tasks/flutter_gallery__transition_perf_e2e_ios32.dart b/dev/devicelab/bin/tasks/flutter_gallery__transition_perf_e2e_ios32.dart
index 88d6b3f2ff..4792368b91 100644
--- a/dev/devicelab/bin/tasks/flutter_gallery__transition_perf_e2e_ios32.dart
+++ b/dev/devicelab/bin/tasks/flutter_gallery__transition_perf_e2e_ios32.dart
@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-// @dart = 2.8
-
 import 'package:flutter_devicelab/framework/devices.dart';
 import 'package:flutter_devicelab/framework/framework.dart';
 import 'package:flutter_devicelab/tasks/gallery.dart';
diff --git a/dev/devicelab/bin/tasks/flutter_gallery__transition_perf_hybrid.dart b/dev/devicelab/bin/tasks/flutter_gallery__transition_perf_hybrid.dart
index 8cdbfd4043..ba6afecdec 100644
--- a/dev/devicelab/bin/tasks/flutter_gallery__transition_perf_hybrid.dart
+++ b/dev/devicelab/bin/tasks/flutter_gallery__transition_perf_hybrid.dart
@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-// @dart = 2.8
-
 import 'package:flutter_devicelab/framework/devices.dart';
 import 'package:flutter_devicelab/framework/framework.dart';
 import 'package:flutter_devicelab/tasks/gallery.dart';
diff --git a/dev/devicelab/bin/tasks/flutter_gallery__transition_perf_with_semantics.dart b/dev/devicelab/bin/tasks/flutter_gallery__transition_perf_with_semantics.dart
index 7338d3dc0d..f76962da86 100644
--- a/dev/devicelab/bin/tasks/flutter_gallery__transition_perf_with_semantics.dart
+++ b/dev/devicelab/bin/tasks/flutter_gallery__transition_perf_with_semantics.dart
@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-// @dart = 2.8
-
 import 'package:flutter_devicelab/framework/devices.dart';
 import 'package:flutter_devicelab/framework/framework.dart';
 import 'package:flutter_devicelab/framework/task_result.dart';
@@ -14,11 +12,13 @@ Future<void> main() async {
   await task(() async {
     final TaskResult withoutSemantics = await createGalleryTransitionTest()();
     final TaskResult withSemantics = await createGalleryTransitionTest(semanticsEnabled: true)();
-    if (withSemantics.benchmarkScoreKeys.isEmpty || withoutSemantics.benchmarkScoreKeys.isEmpty) {
+    final bool withSemanticsDataMissing = withSemantics.benchmarkScoreKeys == null || withSemantics.benchmarkScoreKeys!.isEmpty;
+    final bool withoutSemanticsDataMissing = withoutSemantics.benchmarkScoreKeys == null || withoutSemantics.benchmarkScoreKeys!.isEmpty;
+    if (withSemanticsDataMissing || withoutSemanticsDataMissing) {
       String message = 'Lack of data';
-      if (withSemantics.benchmarkScoreKeys.isEmpty) {
+      if (withSemanticsDataMissing) {
         message += ' for test with semantics';
-        if (withoutSemantics.benchmarkScoreKeys.isEmpty) {
+        if (withoutSemanticsDataMissing) {
           message += ' and without semantics';
         }
       } else {
@@ -29,11 +29,11 @@ Future<void> main() async {
 
     final List<String> benchmarkScoreKeys = <String>[];
     final Map<String, dynamic> data = <String, dynamic>{};
-    for (final String key in withSemantics.benchmarkScoreKeys) {
+    for (final String key in withSemantics.benchmarkScoreKeys!) {
       final String deltaKey = 'delta_$key';
-      data[deltaKey] = (withSemantics.data[key] as num) - (withoutSemantics.data[key] as num);
-      data['semantics_$key'] = withSemantics.data[key];
-      data[key] = withoutSemantics.data[key];
+      data[deltaKey] = (withSemantics.data![key] as num) - (withoutSemantics.data![key] as num);
+      data['semantics_$key'] = withSemantics.data![key];
+      data[key] = withoutSemantics.data![key];
       benchmarkScoreKeys.add(deltaKey);
     }
 
diff --git a/dev/devicelab/bin/tasks/flutter_gallery_android__compile.dart b/dev/devicelab/bin/tasks/flutter_gallery_android__compile.dart
index 3d43575dfa..661b36f997 100644
--- a/dev/devicelab/bin/tasks/flutter_gallery_android__compile.dart
+++ b/dev/devicelab/bin/tasks/flutter_gallery_android__compile.dart
@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-// @dart = 2.8
-
 import 'package:flutter_devicelab/framework/devices.dart';
 import 'package:flutter_devicelab/framework/framework.dart';
 import 'package:flutter_devicelab/tasks/perf_tests.dart';
diff --git a/dev/devicelab/bin/tasks/flutter_gallery_instrumentation_test.dart b/dev/devicelab/bin/tasks/flutter_gallery_instrumentation_test.dart
index 19885bac24..03651ff2b4 100644
--- a/dev/devicelab/bin/tasks/flutter_gallery_instrumentation_test.dart
+++ b/dev/devicelab/bin/tasks/flutter_gallery_instrumentation_test.dart
@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-// @dart = 2.8
-
 import 'dart:io';
 
 import 'package:flutter_devicelab/framework/devices.dart';
@@ -27,9 +25,11 @@ Future<void> main() async {
       await flutter('packages', options: <String>['get']);
       await flutter('clean');
       await flutter('build', options: <String>['apk', '--target', 'test/live_smoketest.dart']);
-      await exec('./tool/run_instrumentation_test.sh', <String>[], environment: <String, String>{
-        'JAVA_HOME': await findJavaHome(),
-      });
+      final String? javaHome = await findJavaHome();
+      final Map<String, String>? environment = javaHome != null
+        ? <String, String>{ 'JAVA_HOME': javaHome }
+        : null;
+      await exec('./tool/run_instrumentation_test.sh', <String>[], environment: environment);
     });
 
     return TaskResult.success(null);
diff --git a/dev/devicelab/bin/tasks/flutter_gallery_ios__compile.dart b/dev/devicelab/bin/tasks/flutter_gallery_ios__compile.dart
index 9e6220b971..92718c3c4a 100644
--- a/dev/devicelab/bin/tasks/flutter_gallery_ios__compile.dart
+++ b/dev/devicelab/bin/tasks/flutter_gallery_ios__compile.dart
@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-// @dart = 2.8
-
 import 'package:flutter_devicelab/framework/devices.dart';
 import 'package:flutter_devicelab/framework/framework.dart';
 import 'package:flutter_devicelab/tasks/perf_tests.dart';
diff --git a/dev/devicelab/bin/tasks/flutter_gallery_ios__start_up.dart b/dev/devicelab/bin/tasks/flutter_gallery_ios__start_up.dart
index bbf70ea26a..86c590ca73 100644
--- a/dev/devicelab/bin/tasks/flutter_gallery_ios__start_up.dart
+++ b/dev/devicelab/bin/tasks/flutter_gallery_ios__start_up.dart
@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-// @dart = 2.8
-
 import 'package:flutter_devicelab/framework/devices.dart';
 import 'package:flutter_devicelab/framework/framework.dart';
 import 'package:flutter_devicelab/tasks/perf_tests.dart';
diff --git a/dev/devicelab/bin/tasks/flutter_gallery_ios__transition_perf.dart b/dev/devicelab/bin/tasks/flutter_gallery_ios__transition_perf.dart
index 25f990e931..4b16f5dd21 100644
--- a/dev/devicelab/bin/tasks/flutter_gallery_ios__transition_perf.dart
+++ b/dev/devicelab/bin/tasks/flutter_gallery_ios__transition_perf.dart
@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-// @dart = 2.8
-
 import 'package:flutter_devicelab/framework/devices.dart';
 import 'package:flutter_devicelab/framework/framework.dart';
 import 'package:flutter_devicelab/tasks/gallery.dart';
diff --git a/dev/devicelab/bin/tasks/flutter_gallery_sksl_warmup__transition_perf.dart b/dev/devicelab/bin/tasks/flutter_gallery_sksl_warmup__transition_perf.dart
index eb1f3279a8..42e32ea97d 100644
--- a/dev/devicelab/bin/tasks/flutter_gallery_sksl_warmup__transition_perf.dart
+++ b/dev/devicelab/bin/tasks/flutter_gallery_sksl_warmup__transition_perf.dart
@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-// @dart = 2.8
-
 import 'package:flutter_devicelab/framework/devices.dart';
 import 'package:flutter_devicelab/framework/framework.dart';
 import 'package:flutter_devicelab/tasks/perf_tests.dart';
diff --git a/dev/devicelab/bin/tasks/flutter_gallery_sksl_warmup__transition_perf_e2e.dart b/dev/devicelab/bin/tasks/flutter_gallery_sksl_warmup__transition_perf_e2e.dart
index 5eb6cc94a3..4baec122db 100644
--- a/dev/devicelab/bin/tasks/flutter_gallery_sksl_warmup__transition_perf_e2e.dart
+++ b/dev/devicelab/bin/tasks/flutter_gallery_sksl_warmup__transition_perf_e2e.dart
@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-// @dart = 2.8
-
 import 'package:flutter_devicelab/framework/devices.dart';
 import 'package:flutter_devicelab/framework/framework.dart';
 import 'package:flutter_devicelab/tasks/perf_tests.dart';
diff --git a/dev/devicelab/bin/tasks/flutter_gallery_v2_chrome_run_test.dart b/dev/devicelab/bin/tasks/flutter_gallery_v2_chrome_run_test.dart
index 286e8858b6..266c672d72 100644
--- a/dev/devicelab/bin/tasks/flutter_gallery_v2_chrome_run_test.dart
+++ b/dev/devicelab/bin/tasks/flutter_gallery_v2_chrome_run_test.dart
@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-// @dart = 2.8
-
 import 'dart:async';
 import 'dart:convert';
 import 'dart:io';
diff --git a/dev/devicelab/bin/tasks/flutter_gallery_v2_web_compile_test.dart b/dev/devicelab/bin/tasks/flutter_gallery_v2_web_compile_test.dart
index fbb598a9ee..1356645d0e 100644
--- a/dev/devicelab/bin/tasks/flutter_gallery_v2_web_compile_test.dart
+++ b/dev/devicelab/bin/tasks/flutter_gallery_v2_web_compile_test.dart
@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-// @dart = 2.8
-
 import 'dart:io';
 
 import 'package:flutter_devicelab/framework/framework.dart';
diff --git a/dev/devicelab/bin/tasks/flutter_gallery_win__compile.dart b/dev/devicelab/bin/tasks/flutter_gallery_win__compile.dart
index 3d43575dfa..661b36f997 100644
--- a/dev/devicelab/bin/tasks/flutter_gallery_win__compile.dart
+++ b/dev/devicelab/bin/tasks/flutter_gallery_win__compile.dart
@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-// @dart = 2.8
-
 import 'package:flutter_devicelab/framework/devices.dart';
 import 'package:flutter_devicelab/framework/framework.dart';
 import 'package:flutter_devicelab/tasks/perf_tests.dart';
diff --git a/dev/devicelab/bin/tasks/flutter_run_test.dart b/dev/devicelab/bin/tasks/flutter_run_test.dart
index 9a5cdbf39d..b72154cc2f 100644
--- a/dev/devicelab/bin/tasks/flutter_run_test.dart
+++ b/dev/devicelab/bin/tasks/flutter_run_test.dart
@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-// @dart = 2.8
-
 import 'dart:async';
 import 'dart:convert';
 import 'dart:io';
diff --git a/dev/devicelab/bin/tasks/flutter_test_performance.dart b/dev/devicelab/bin/tasks/flutter_test_performance.dart
index 4384523b78..0bbee03c56 100644
--- a/dev/devicelab/bin/tasks/flutter_test_performance.dart
+++ b/dev/devicelab/bin/tasks/flutter_test_performance.dart
@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-// @dart = 2.8
-
 // This test runs `flutter test` on the `trivial_widget_test.dart` four times.
 //
 // The first time, the result is ignored, on the basis that it's warming the
@@ -67,11 +65,11 @@ Future<int> runTest({bool coverage = false, bool noPub = false}) async {
       // we have a blank line at the start
       step = TestStep.testWritesFirstCarriageReturn;
     } else {
-      final Match match = testOutputPattern.matchAsPrefix(entry);
+      final Match? match = testOutputPattern.matchAsPrefix(entry);
       if (match == null) {
         badLines += 1;
       } else {
-        if (step.index >= TestStep.testWritesFirstCarriageReturn.index && step.index <= TestStep.testLoading.index && match.group(1).startsWith('loading ')) {
+        if (step.index >= TestStep.testWritesFirstCarriageReturn.index && step.index <= TestStep.testLoading.index && match.group(1)!.startsWith('loading ')) {
           // first the test loads
           step = TestStep.testLoading;
         } else if (step.index <= TestStep.testRunning.index && match.group(1) == 'A trivial widget test') {
diff --git a/dev/devicelab/bin/tasks/flutter_view__start_up.dart b/dev/devicelab/bin/tasks/flutter_view__start_up.dart
index ca9345e1bf..a660b48273 100644
--- a/dev/devicelab/bin/tasks/flutter_view__start_up.dart
+++ b/dev/devicelab/bin/tasks/flutter_view__start_up.dart
@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-// @dart = 2.8
-
 import 'package:flutter_devicelab/framework/devices.dart';
 import 'package:flutter_devicelab/framework/framework.dart';
 import 'package:flutter_devicelab/tasks/perf_tests.dart';
diff --git a/dev/devicelab/bin/tasks/flutter_view_ios__start_up.dart b/dev/devicelab/bin/tasks/flutter_view_ios__start_up.dart
index c6e1350ac3..ad12b046dd 100644
--- a/dev/devicelab/bin/tasks/flutter_view_ios__start_up.dart
+++ b/dev/devicelab/bin/tasks/flutter_view_ios__start_up.dart
@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-// @dart = 2.8
-
 import 'package:flutter_devicelab/framework/devices.dart';
 import 'package:flutter_devicelab/framework/framework.dart';
 import 'package:flutter_devicelab/tasks/perf_tests.dart';
diff --git a/dev/devicelab/bin/tasks/frame_policy_delay_test_android.dart b/dev/devicelab/bin/tasks/frame_policy_delay_test_android.dart
index 835792e31c..14d581de54 100644
--- a/dev/devicelab/bin/tasks/frame_policy_delay_test_android.dart
+++ b/dev/devicelab/bin/tasks/frame_policy_delay_test_android.dart
@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-// @dart = 2.8
-
 import 'package:flutter_devicelab/framework/devices.dart';
 import 'package:flutter_devicelab/framework/framework.dart';
 import 'package:flutter_devicelab/tasks/perf_tests.dart';
diff --git a/dev/devicelab/bin/tasks/fullscreen_textfield_perf.dart b/dev/devicelab/bin/tasks/fullscreen_textfield_perf.dart
index a58be1cd9b..c0710805e2 100644
--- a/dev/devicelab/bin/tasks/fullscreen_textfield_perf.dart
+++ b/dev/devicelab/bin/tasks/fullscreen_textfield_perf.dart
@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-// @dart = 2.8
-
 import 'package:flutter_devicelab/framework/devices.dart';
 import 'package:flutter_devicelab/framework/framework.dart';
 import 'package:flutter_devicelab/tasks/perf_tests.dart';
diff --git a/dev/devicelab/bin/tasks/fullscreen_textfield_perf__e2e_summary.dart b/dev/devicelab/bin/tasks/fullscreen_textfield_perf__e2e_summary.dart
index 7bb7ab7cea..508cc0842a 100644
--- a/dev/devicelab/bin/tasks/fullscreen_textfield_perf__e2e_summary.dart
+++ b/dev/devicelab/bin/tasks/fullscreen_textfield_perf__e2e_summary.dart
@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-// @dart = 2.8
-
 import 'dart:async';
 
 import 'package:flutter_devicelab/framework/devices.dart';
diff --git a/dev/devicelab/bin/tasks/fullscreen_textfield_perf__timeline_summary.dart b/dev/devicelab/bin/tasks/fullscreen_textfield_perf__timeline_summary.dart
index a58be1cd9b..c0710805e2 100644
--- a/dev/devicelab/bin/tasks/fullscreen_textfield_perf__timeline_summary.dart
+++ b/dev/devicelab/bin/tasks/fullscreen_textfield_perf__timeline_summary.dart
@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-// @dart = 2.8
-
 import 'package:flutter_devicelab/framework/devices.dart';
 import 'package:flutter_devicelab/framework/framework.dart';
 import 'package:flutter_devicelab/tasks/perf_tests.dart';
diff --git a/dev/devicelab/bin/tasks/gradle_desugar_classes_test.dart b/dev/devicelab/bin/tasks/gradle_desugar_classes_test.dart
index 6d76405e5f..4fe64d52d0 100644
--- a/dev/devicelab/bin/tasks/gradle_desugar_classes_test.dart
+++ b/dev/devicelab/bin/tasks/gradle_desugar_classes_test.dart
@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-// @dart = 2.8
-
 import 'dart:io';
 
 import 'package:flutter_devicelab/framework/apk_utils.dart';
diff --git a/dev/devicelab/bin/tasks/gradle_java8_compile_test.dart b/dev/devicelab/bin/tasks/gradle_java8_compile_test.dart
index 0a73a17df7..64581e593c 100644
--- a/dev/devicelab/bin/tasks/gradle_java8_compile_test.dart
+++ b/dev/devicelab/bin/tasks/gradle_java8_compile_test.dart
@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-// @dart = 2.8
-
 import 'dart:io';
 
 import 'package:flutter_devicelab/framework/apk_utils.dart';
diff --git a/dev/devicelab/bin/tasks/gradle_migrate_settings_test.dart b/dev/devicelab/bin/tasks/gradle_migrate_settings_test.dart
index a36afbba41..46ed8539e4 100644
--- a/dev/devicelab/bin/tasks/gradle_migrate_settings_test.dart
+++ b/dev/devicelab/bin/tasks/gradle_migrate_settings_test.dart
@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-// @dart = 2.8
-
 import 'dart:io';
 
 import 'package:flutter_devicelab/framework/framework.dart';
@@ -20,7 +18,7 @@ Future<void> main() async {
 
     section('Find Java');
 
-    final String javaHome = await findJavaHome();
+    final String? javaHome = await findJavaHome();
     if (javaHome == null)
       return TaskResult.failure('Could not find Java');
     print('\nUsing JAVA_HOME=$javaHome');
@@ -43,7 +41,7 @@ Future<void> main() async {
 
       section('Build APK');
 
-      String stdout;
+      late String stdout;
       await inDirectory(projectDir, () async {
         stdout = await evalFlutter(
           'build',
diff --git a/dev/devicelab/bin/tasks/gradle_non_android_plugin_test.dart b/dev/devicelab/bin/tasks/gradle_non_android_plugin_test.dart
index ca9454d51c..5507f20097 100644
--- a/dev/devicelab/bin/tasks/gradle_non_android_plugin_test.dart
+++ b/dev/devicelab/bin/tasks/gradle_non_android_plugin_test.dart
@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-// @dart = 2.8
-
 import 'package:flutter_devicelab/framework/framework.dart';
 import 'package:flutter_devicelab/framework/task_result.dart';
 
diff --git a/dev/devicelab/bin/tasks/gradle_plugin_bundle_test.dart b/dev/devicelab/bin/tasks/gradle_plugin_bundle_test.dart
index 3e6a690202..c5add22fab 100644
--- a/dev/devicelab/bin/tasks/gradle_plugin_bundle_test.dart
+++ b/dev/devicelab/bin/tasks/gradle_plugin_bundle_test.dart
@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-// @dart = 2.8
-
 import 'package:flutter_devicelab/framework/apk_utils.dart';
 import 'package:flutter_devicelab/framework/framework.dart';
 import 'package:flutter_devicelab/framework/task_result.dart';
diff --git a/dev/devicelab/bin/tasks/gradle_plugin_fat_apk_test.dart b/dev/devicelab/bin/tasks/gradle_plugin_fat_apk_test.dart
index 53f6d6a1ce..868b2d4436 100644
--- a/dev/devicelab/bin/tasks/gradle_plugin_fat_apk_test.dart
+++ b/dev/devicelab/bin/tasks/gradle_plugin_fat_apk_test.dart
@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-// @dart = 2.8
-
 import 'dart:io';
 
 import 'package:flutter_devicelab/framework/apk_utils.dart';
diff --git a/dev/devicelab/bin/tasks/gradle_plugin_light_apk_test.dart b/dev/devicelab/bin/tasks/gradle_plugin_light_apk_test.dart
index 97cbbc58be..a4b2ef47f8 100644
--- a/dev/devicelab/bin/tasks/gradle_plugin_light_apk_test.dart
+++ b/dev/devicelab/bin/tasks/gradle_plugin_light_apk_test.dart
@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-// @dart = 2.8
-
 import 'dart:io';
 
 import 'package:flutter_devicelab/framework/apk_utils.dart';
@@ -177,7 +175,7 @@ Future<void> main() async {
             ],
           );
         });
-        final String errorMessage = validateSnapshotDependency(project, 'kernel_blob.bin');
+        final String? errorMessage = validateSnapshotDependency(project, 'kernel_blob.bin');
         if (errorMessage != null) {
           throw TaskResult.failure(errorMessage);
         }
diff --git a/dev/devicelab/bin/tasks/hello_world__memory.dart b/dev/devicelab/bin/tasks/hello_world__memory.dart
index 9da7c378b8..60fa3e1a08 100644
--- a/dev/devicelab/bin/tasks/hello_world__memory.dart
+++ b/dev/devicelab/bin/tasks/hello_world__memory.dart
@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-// @dart = 2.8
-
 import 'package:flutter_devicelab/framework/framework.dart';
 import 'package:flutter_devicelab/framework/utils.dart';
 import 'package:flutter_devicelab/tasks/perf_tests.dart';
@@ -24,7 +22,7 @@ class HelloWorldMemoryTest extends MemoryTest {
       '--verbose',
       '--release',
       '--no-resident',
-      '-d', device.deviceId,
+      '-d', device!.deviceId,
       test,
     ]);
     await Future<void>.delayed(const Duration(milliseconds: 1500));
diff --git a/dev/devicelab/bin/tasks/hello_world_android__compile.dart b/dev/devicelab/bin/tasks/hello_world_android__compile.dart
index 279cf62b0a..e515cd9869 100644
--- a/dev/devicelab/bin/tasks/hello_world_android__compile.dart
+++ b/dev/devicelab/bin/tasks/hello_world_android__compile.dart
@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-// @dart = 2.8
-
 import 'package:flutter_devicelab/framework/devices.dart';
 import 'package:flutter_devicelab/framework/framework.dart';
 import 'package:flutter_devicelab/tasks/perf_tests.dart';
diff --git a/dev/devicelab/bin/tasks/hello_world_ios__compile.dart b/dev/devicelab/bin/tasks/hello_world_ios__compile.dart
index 8e57f2c651..2f5a68f955 100644
--- a/dev/devicelab/bin/tasks/hello_world_ios__compile.dart
+++ b/dev/devicelab/bin/tasks/hello_world_ios__compile.dart
@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-// @dart = 2.8
-
 import 'package:flutter_devicelab/framework/devices.dart';
 import 'package:flutter_devicelab/framework/framework.dart';
 import 'package:flutter_devicelab/tasks/perf_tests.dart';
diff --git a/dev/devicelab/bin/tasks/home_scroll_perf__timeline_summary.dart b/dev/devicelab/bin/tasks/home_scroll_perf__timeline_summary.dart
index 72f80a81c4..8bdb288a0d 100644
--- a/dev/devicelab/bin/tasks/home_scroll_perf__timeline_summary.dart
+++ b/dev/devicelab/bin/tasks/home_scroll_perf__timeline_summary.dart
@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-// @dart = 2.8
-
 import 'package:flutter_devicelab/framework/devices.dart';
 import 'package:flutter_devicelab/framework/framework.dart';
 import 'package:flutter_devicelab/tasks/perf_tests.dart';
diff --git a/dev/devicelab/bin/tasks/hot_mode_dev_cycle__benchmark.dart b/dev/devicelab/bin/tasks/hot_mode_dev_cycle__benchmark.dart
index 6b79008997..4352d9e928 100644
--- a/dev/devicelab/bin/tasks/hot_mode_dev_cycle__benchmark.dart
+++ b/dev/devicelab/bin/tasks/hot_mode_dev_cycle__benchmark.dart
@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-// @dart = 2.8
-
 import 'package:flutter_devicelab/framework/framework.dart';
 import 'package:flutter_devicelab/tasks/hot_mode_tests.dart';
 
diff --git a/dev/devicelab/bin/tasks/hot_mode_dev_cycle_linux__benchmark.dart b/dev/devicelab/bin/tasks/hot_mode_dev_cycle_linux__benchmark.dart
index 6b79008997..4352d9e928 100644
--- a/dev/devicelab/bin/tasks/hot_mode_dev_cycle_linux__benchmark.dart
+++ b/dev/devicelab/bin/tasks/hot_mode_dev_cycle_linux__benchmark.dart
@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-// @dart = 2.8
-
 import 'package:flutter_devicelab/framework/framework.dart';
 import 'package:flutter_devicelab/tasks/hot_mode_tests.dart';
 
diff --git a/dev/devicelab/bin/tasks/hot_mode_dev_cycle_linux_target__benchmark.dart b/dev/devicelab/bin/tasks/hot_mode_dev_cycle_linux_target__benchmark.dart
index 9b41920987..8c49bea1c6 100644
--- a/dev/devicelab/bin/tasks/hot_mode_dev_cycle_linux_target__benchmark.dart
+++ b/dev/devicelab/bin/tasks/hot_mode_dev_cycle_linux_target__benchmark.dart
@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-// @dart = 2.8
-
 import 'package:flutter_devicelab/framework/framework.dart';
 import 'package:flutter_devicelab/tasks/hot_mode_tests.dart';
 
diff --git a/dev/devicelab/bin/tasks/hot_mode_dev_cycle_macos_target__benchmark.dart b/dev/devicelab/bin/tasks/hot_mode_dev_cycle_macos_target__benchmark.dart
index 633050d03c..25e4f4d5c1 100644
--- a/dev/devicelab/bin/tasks/hot_mode_dev_cycle_macos_target__benchmark.dart
+++ b/dev/devicelab/bin/tasks/hot_mode_dev_cycle_macos_target__benchmark.dart
@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-// @dart = 2.8
-
 import 'package:flutter_devicelab/framework/framework.dart';
 import 'package:flutter_devicelab/tasks/hot_mode_tests.dart';
 
diff --git a/dev/devicelab/bin/tasks/hot_mode_dev_cycle_win__benchmark.dart b/dev/devicelab/bin/tasks/hot_mode_dev_cycle_win__benchmark.dart
index 6b79008997..4352d9e928 100644
--- a/dev/devicelab/bin/tasks/hot_mode_dev_cycle_win__benchmark.dart
+++ b/dev/devicelab/bin/tasks/hot_mode_dev_cycle_win__benchmark.dart
@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-// @dart = 2.8
-
 import 'package:flutter_devicelab/framework/framework.dart';
 import 'package:flutter_devicelab/tasks/hot_mode_tests.dart';
 
diff --git a/dev/devicelab/bin/tasks/hot_mode_dev_cycle_win_target__benchmark.dart b/dev/devicelab/bin/tasks/hot_mode_dev_cycle_win_target__benchmark.dart
index b096ccad02..7262edea63 100644
--- a/dev/devicelab/bin/tasks/hot_mode_dev_cycle_win_target__benchmark.dart
+++ b/dev/devicelab/bin/tasks/hot_mode_dev_cycle_win_target__benchmark.dart
@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-// @dart = 2.8
-
 import 'package:flutter_devicelab/framework/framework.dart';
 import 'package:flutter_devicelab/tasks/hot_mode_tests.dart';
 
diff --git a/dev/devicelab/bin/tasks/hybrid_android_views_integration_test.dart b/dev/devicelab/bin/tasks/hybrid_android_views_integration_test.dart
index 0bf1d17401..156b81bbc1 100644
--- a/dev/devicelab/bin/tasks/hybrid_android_views_integration_test.dart
+++ b/dev/devicelab/bin/tasks/hybrid_android_views_integration_test.dart
@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-// @dart = 2.8
-
 import 'package:flutter_devicelab/framework/devices.dart';
 import 'package:flutter_devicelab/framework/framework.dart';
 import 'package:flutter_devicelab/tasks/integration_tests.dart';
diff --git a/dev/devicelab/bin/tasks/image_list_jit_reported_duration.dart b/dev/devicelab/bin/tasks/image_list_jit_reported_duration.dart
index 1f7d8585c5..1605f36d36 100644
--- a/dev/devicelab/bin/tasks/image_list_jit_reported_duration.dart
+++ b/dev/devicelab/bin/tasks/image_list_jit_reported_duration.dart
@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-// @dart = 2.8
-
 import 'package:flutter_devicelab/framework/framework.dart';
 import 'package:flutter_devicelab/framework/utils.dart';
 import 'package:flutter_devicelab/tasks/perf_tests.dart';
diff --git a/dev/devicelab/bin/tasks/image_list_reported_duration.dart b/dev/devicelab/bin/tasks/image_list_reported_duration.dart
index 8a4f94e6fd..221c971d94 100644
--- a/dev/devicelab/bin/tasks/image_list_reported_duration.dart
+++ b/dev/devicelab/bin/tasks/image_list_reported_duration.dart
@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-// @dart = 2.8
-
 import 'package:flutter_devicelab/framework/framework.dart';
 import 'package:flutter_devicelab/framework/utils.dart';
 import 'package:flutter_devicelab/tasks/perf_tests.dart';
diff --git a/dev/devicelab/bin/tasks/imagefiltered_transform_animation_perf__timeline_summary.dart b/dev/devicelab/bin/tasks/imagefiltered_transform_animation_perf__timeline_summary.dart
index 0b8e3a1632..a6aaccedd4 100644
--- a/dev/devicelab/bin/tasks/imagefiltered_transform_animation_perf__timeline_summary.dart
+++ b/dev/devicelab/bin/tasks/imagefiltered_transform_animation_perf__timeline_summary.dart
@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-// @dart = 2.8
-
 import 'package:flutter_devicelab/framework/devices.dart';
 import 'package:flutter_devicelab/framework/framework.dart';
 import 'package:flutter_devicelab/tasks/perf_tests.dart';
diff --git a/dev/devicelab/bin/tasks/integration_test_test.dart b/dev/devicelab/bin/tasks/integration_test_test.dart
index d4a0ea8830..5ea97f0815 100644
--- a/dev/devicelab/bin/tasks/integration_test_test.dart
+++ b/dev/devicelab/bin/tasks/integration_test_test.dart
@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-// @dart = 2.8
-
 import 'package:flutter_devicelab/framework/devices.dart';
 import 'package:flutter_devicelab/framework/framework.dart';
 import 'package:flutter_devicelab/tasks/integration_tests.dart';
diff --git a/dev/devicelab/bin/tasks/integration_test_test_ios.dart b/dev/devicelab/bin/tasks/integration_test_test_ios.dart
index c68feab69e..1d492b22f3 100644
--- a/dev/devicelab/bin/tasks/integration_test_test_ios.dart
+++ b/dev/devicelab/bin/tasks/integration_test_test_ios.dart
@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-// @dart = 2.8
-
 import 'package:flutter_devicelab/framework/devices.dart';
 import 'package:flutter_devicelab/framework/framework.dart';
 import 'package:flutter_devicelab/tasks/integration_tests.dart';
diff --git a/dev/devicelab/bin/tasks/integration_ui_driver.dart b/dev/devicelab/bin/tasks/integration_ui_driver.dart
index f677fa43de..7e49e6b21a 100644
--- a/dev/devicelab/bin/tasks/integration_ui_driver.dart
+++ b/dev/devicelab/bin/tasks/integration_ui_driver.dart
@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-// @dart = 2.8
-
 import 'package:flutter_devicelab/framework/devices.dart';
 import 'package:flutter_devicelab/framework/framework.dart';
 import 'package:flutter_devicelab/tasks/integration_tests.dart';
diff --git a/dev/devicelab/bin/tasks/integration_ui_ios_driver.dart b/dev/devicelab/bin/tasks/integration_ui_ios_driver.dart
index ebe41478f2..20cc0d3655 100644
--- a/dev/devicelab/bin/tasks/integration_ui_ios_driver.dart
+++ b/dev/devicelab/bin/tasks/integration_ui_ios_driver.dart
@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-// @dart = 2.8
-
 import 'package:flutter_devicelab/framework/devices.dart';
 import 'package:flutter_devicelab/framework/framework.dart';
 import 'package:flutter_devicelab/tasks/integration_tests.dart';
diff --git a/dev/devicelab/bin/tasks/integration_ui_ios_keyboard_resize.dart b/dev/devicelab/bin/tasks/integration_ui_ios_keyboard_resize.dart
index 1945e8f09c..0d8e84ae2a 100644
--- a/dev/devicelab/bin/tasks/integration_ui_ios_keyboard_resize.dart
+++ b/dev/devicelab/bin/tasks/integration_ui_ios_keyboard_resize.dart
@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-// @dart = 2.8
-
 import 'package:flutter_devicelab/framework/devices.dart';
 import 'package:flutter_devicelab/framework/framework.dart';
 import 'package:flutter_devicelab/tasks/integration_tests.dart';
diff --git a/dev/devicelab/bin/tasks/integration_ui_ios_screenshot.dart b/dev/devicelab/bin/tasks/integration_ui_ios_screenshot.dart
index 7d208c9d36..49bb51d654 100644
--- a/dev/devicelab/bin/tasks/integration_ui_ios_screenshot.dart
+++ b/dev/devicelab/bin/tasks/integration_ui_ios_screenshot.dart
@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-// @dart = 2.8
-
 import 'package:flutter_devicelab/framework/devices.dart';
 import 'package:flutter_devicelab/framework/framework.dart';
 import 'package:flutter_devicelab/tasks/integration_tests.dart';
diff --git a/dev/devicelab/bin/tasks/integration_ui_ios_textfield.dart b/dev/devicelab/bin/tasks/integration_ui_ios_textfield.dart
index cd92e0db1d..1708f539f1 100644
--- a/dev/devicelab/bin/tasks/integration_ui_ios_textfield.dart
+++ b/dev/devicelab/bin/tasks/integration_ui_ios_textfield.dart
@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-// @dart = 2.8
-
 import 'package:flutter_devicelab/framework/devices.dart';
 import 'package:flutter_devicelab/framework/framework.dart';
 import 'package:flutter_devicelab/tasks/integration_tests.dart';
diff --git a/dev/devicelab/bin/tasks/integration_ui_keyboard_resize.dart b/dev/devicelab/bin/tasks/integration_ui_keyboard_resize.dart
index 360ded7e08..54c2f046dd 100644
--- a/dev/devicelab/bin/tasks/integration_ui_keyboard_resize.dart
+++ b/dev/devicelab/bin/tasks/integration_ui_keyboard_resize.dart
@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-// @dart = 2.8
-
 import 'package:flutter_devicelab/framework/devices.dart';
 import 'package:flutter_devicelab/framework/framework.dart';
 import 'package:flutter_devicelab/tasks/integration_tests.dart';
diff --git a/dev/devicelab/bin/tasks/integration_ui_screenshot.dart b/dev/devicelab/bin/tasks/integration_ui_screenshot.dart
index 3717fd9d5d..4a3c8cabbd 100644
--- a/dev/devicelab/bin/tasks/integration_ui_screenshot.dart
+++ b/dev/devicelab/bin/tasks/integration_ui_screenshot.dart
@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-// @dart = 2.8
-
 import 'package:flutter_devicelab/framework/devices.dart';
 import 'package:flutter_devicelab/framework/framework.dart';
 import 'package:flutter_devicelab/tasks/integration_tests.dart';
diff --git a/dev/devicelab/bin/tasks/integration_ui_textfield.dart b/dev/devicelab/bin/tasks/integration_ui_textfield.dart
index 616674c700..ff42d58310 100644
--- a/dev/devicelab/bin/tasks/integration_ui_textfield.dart
+++ b/dev/devicelab/bin/tasks/integration_ui_textfield.dart
@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-// @dart = 2.8
-
 import 'package:flutter_devicelab/framework/devices.dart';
 import 'package:flutter_devicelab/framework/framework.dart';
 import 'package:flutter_devicelab/tasks/integration_tests.dart';