diff --git a/dev/integration_tests/ui/ios/Flutter/Debug.xcconfig b/dev/integration_tests/ui/ios/Flutter/Debug.xcconfig
index 592ceee85b8..ec97fc6f302 100644
--- a/dev/integration_tests/ui/ios/Flutter/Debug.xcconfig
+++ b/dev/integration_tests/ui/ios/Flutter/Debug.xcconfig
@@ -1 +1,2 @@
+#include? "Pods/Target Support Files/Pods-Runner/Pods-Runner.debug.xcconfig"
 #include "Generated.xcconfig"
diff --git a/dev/integration_tests/ui/ios/Flutter/Release.xcconfig b/dev/integration_tests/ui/ios/Flutter/Release.xcconfig
index 592ceee85b8..c4855bfe200 100644
--- a/dev/integration_tests/ui/ios/Flutter/Release.xcconfig
+++ b/dev/integration_tests/ui/ios/Flutter/Release.xcconfig
@@ -1 +1,2 @@
+#include? "Pods/Target Support Files/Pods-Runner/Pods-Runner.release.xcconfig"
 #include "Generated.xcconfig"
diff --git a/dev/integration_tests/ui/lib/commands.dart b/dev/integration_tests/ui/lib/commands.dart
index 512c9cb2007..e665a09ddf1 100644
--- a/dev/integration_tests/ui/lib/commands.dart
+++ b/dev/integration_tests/ui/lib/commands.dart
@@ -11,14 +11,14 @@ void main() {
 }
 
 class Test extends SingleChildRenderObjectWidget {
-  const Test({ Key key }) : super(key: key);
+  const Test({ Key? key }) : super(key: key);
 
   @override
   RenderTest createRenderObject(BuildContext context) => RenderTest();
 }
 
 class RenderTest extends RenderProxyBox {
-  RenderTest({ RenderBox child }) : super(child);
+  RenderTest({ RenderBox? child }) : super(child);
 
   @override
   void debugPaintSize(PaintingContext context, Offset offset) {
diff --git a/dev/integration_tests/ui/lib/driver.dart b/dev/integration_tests/ui/lib/driver.dart
index 541030e5942..95246567db4 100644
--- a/dev/integration_tests/ui/lib/driver.dart
+++ b/dev/integration_tests/ui/lib/driver.dart
@@ -11,7 +11,7 @@ void main() {
 }
 
 class DriverTestApp extends StatefulWidget {
-  const DriverTestApp({Key key}) : super(key: key);
+  const DriverTestApp({Key? key}) : super(key: key);
 
   @override
   State<StatefulWidget> createState() {
@@ -59,9 +59,9 @@ class DriverTestAppState extends State<DriverTestApp> {
                 DropdownButton<Letter>(
                   key: const ValueKey<String>('dropdown'),
                   value: _selectedValue,
-                  onChanged: (Letter newValue) {
+                  onChanged: (Letter? newValue) {
                     setState(() {
-                      _selectedValue = newValue;
+                      _selectedValue = newValue!;
                     });
                   },
                   items: const <DropdownMenuItem<Letter>>[
diff --git a/dev/integration_tests/ui/lib/empty.dart b/dev/integration_tests/ui/lib/empty.dart
index f2adfcfb9dd..a02785c9149 100644
--- a/dev/integration_tests/ui/lib/empty.dart
+++ b/dev/integration_tests/ui/lib/empty.dart
@@ -12,7 +12,7 @@ void main() {
 }
 
 class Empty extends StatelessWidget {
-  const Empty({Key key}) : super(key: key);
+  const Empty({Key? key}) : super(key: key);
 
   @override
   Widget build(BuildContext context) => Container();
diff --git a/dev/integration_tests/ui/lib/keyboard_resize.dart b/dev/integration_tests/ui/lib/keyboard_resize.dart
index 487be447a7b..817d5f24b90 100644
--- a/dev/integration_tests/ui/lib/keyboard_resize.dart
+++ b/dev/integration_tests/ui/lib/keyboard_resize.dart
@@ -8,7 +8,7 @@ import 'package:flutter_driver/driver_extension.dart';
 import 'keys.dart' as keys;
 
 void main() {
-  enableFlutterDriverExtension(handler: (String message) async {
+  enableFlutterDriverExtension(handler: (String? message) async {
     // TODO(cbernaschina): remove when test flakiness is resolved
     return 'keyboard_resize';
   });
@@ -16,7 +16,7 @@ void main() {
 }
 
 class MyApp extends StatelessWidget {
-  const MyApp({Key key}) : super(key: key);
+  const MyApp({Key? key}) : super(key: key);
 
   @override
   Widget build(BuildContext context) {
@@ -29,7 +29,7 @@ class MyApp extends StatelessWidget {
 }
 
 class MyHomePage extends StatefulWidget {
-  const MyHomePage({Key key}) : super(key: key);
+  const MyHomePage({Key? key}) : super(key: key);
 
   @override
   _MyHomePageState createState() => _MyHomePageState();
@@ -60,7 +60,7 @@ class _MyHomePageState extends State<MyHomePage> {
       ),
       floatingActionButton: FloatingActionButton(
         key: const Key(keys.kUnfocusButton),
-        onPressed: () { textField.focusNode.unfocus(); },
+        onPressed: () { textField.focusNode!.unfocus(); },
         tooltip: 'Unfocus',
         child: const Icon(Icons.done),
       ),
diff --git a/dev/integration_tests/ui/lib/keyboard_textfield.dart b/dev/integration_tests/ui/lib/keyboard_textfield.dart
index bb94cd81f5c..78fe8784d3f 100644
--- a/dev/integration_tests/ui/lib/keyboard_textfield.dart
+++ b/dev/integration_tests/ui/lib/keyboard_textfield.dart
@@ -14,7 +14,7 @@ void main() {
 }
 
 class MyApp extends StatelessWidget {
-  const MyApp({Key key}) : super(key: key);
+  const MyApp({Key? key}) : super(key: key);
 
   @override
   Widget build(BuildContext context) {
@@ -27,7 +27,7 @@ class MyApp extends StatelessWidget {
 }
 
 class MyHomePage extends StatefulWidget {
-  const MyHomePage({Key key}) : super(key: key);
+  const MyHomePage({Key? key}) : super(key: key);
 
   @override
   _MyHomePageState createState() => _MyHomePageState();
diff --git a/dev/integration_tests/ui/lib/license_check.dart b/dev/integration_tests/ui/lib/license_check.dart
index 40d56f4b21e..2667a4baec2 100644
--- a/dev/integration_tests/ui/lib/license_check.dart
+++ b/dev/integration_tests/ui/lib/license_check.dart
@@ -14,13 +14,13 @@ void main() {
 }
 
 class ShowLicenses extends StatelessWidget {
-  const ShowLicenses({Key key}) : super(key: key);
+  const ShowLicenses({Key? key}) : super(key: key);
 
   Widget _buildTestResultWidget(
     BuildContext context,
     AsyncSnapshot<List<LicenseEntry>> snapshot,
   ) {
-    final List<LicenseEntry> entries = snapshot.data;
+    final List<LicenseEntry> entries = snapshot.data  ?? <LicenseEntry>[];
     String flutterPackage = '';
     final List<String> flutterParagraphs = <String>[];
     String enginePackage = '';
@@ -41,17 +41,15 @@ class ShowLicenses extends StatelessWidget {
     }
 
     final List<Widget> result = <Widget>[];
-    if (entries.isNotEmpty) {
-      result.addAll(<Widget>[
-        const Text('License Check Test', key: ValueKey<String>('Header')),
-        Text(flutterPackage, key: const ValueKey<String>('FlutterPackage')),
-        Text(flutterParagraphs.join(' '), key: const ValueKey<String>('FlutterLicense')),
-        Text('${flutterParagraphs.length}', key: const ValueKey<String>('FlutterCount')),
-        Text(enginePackage, key: const ValueKey<String>('EnginePackage')),
-        Text(engineParagraphs.join(' '), key: const ValueKey<String>('EngineLicense')),
-        Text('${engineParagraphs.length}', key: const ValueKey<String>('EngineCount')),
-      ]);
-    }
+    result.addAll(<Widget>[
+      const Text('License Check Test', key: ValueKey<String>('Header')),
+      Text(flutterPackage, key: const ValueKey<String>('FlutterPackage')),
+      Text(flutterParagraphs.join(' '), key: const ValueKey<String>('FlutterLicense')),
+      Text('${flutterParagraphs.length}', key: const ValueKey<String>('FlutterCount')),
+      Text(enginePackage, key: const ValueKey<String>('EnginePackage')),
+      Text(engineParagraphs.join(' '), key: const ValueKey<String>('EngineLicense')),
+      Text('${engineParagraphs.length}', key: const ValueKey<String>('EngineCount')),
+    ]);
 
     return ListView(
       children: result,
diff --git a/dev/integration_tests/ui/lib/main.dart b/dev/integration_tests/ui/lib/main.dart
index 2a0f10bd1ae..fa57237f3e9 100644
--- a/dev/integration_tests/ui/lib/main.dart
+++ b/dev/integration_tests/ui/lib/main.dart
@@ -18,9 +18,9 @@ void main() {
               textDirection: TextDirection.ltr,
             ),
             onPressed: () {
-              Navigator.push<Object>(
+              Navigator.push<Object?>(
                 context,
-                MaterialPageRoute<dynamic>(
+                MaterialPageRoute<Object?>(
                   builder: (BuildContext context) {
                     return const Material(
                       child: Center(
diff --git a/dev/integration_tests/ui/lib/overflow.dart b/dev/integration_tests/ui/lib/overflow.dart
index 42e5a13357c..d030e28751a 100644
--- a/dev/integration_tests/ui/lib/overflow.dart
+++ b/dev/integration_tests/ui/lib/overflow.dart
@@ -9,7 +9,7 @@ void main() {
 }
 
 class Test extends StatefulWidget {
-  const Test({ Key key }) : super(key: key);
+  const Test({ Key? key }) : super(key: key);
 
   @override
   State<Test> createState() => _TestState();
diff --git a/dev/integration_tests/ui/lib/route.dart b/dev/integration_tests/ui/lib/route.dart
index 7d2e5c61402..9cf446a58a8 100644
--- a/dev/integration_tests/ui/lib/route.dart
+++ b/dev/integration_tests/ui/lib/route.dart
@@ -9,7 +9,7 @@ import 'package:flutter_driver/driver_extension.dart';
 // To use this test: "flutter drive --route '/smuggle-it' lib/route.dart"
 
 void main() {
-  enableFlutterDriverExtension(handler: (String message) async {
+  enableFlutterDriverExtension(handler: (String? message) async {
     return ui.window.defaultRouteName;
   });
 }
diff --git a/dev/integration_tests/ui/lib/screenshot.dart b/dev/integration_tests/ui/lib/screenshot.dart
index 68a7e60b103..f58dad5604a 100644
--- a/dev/integration_tests/ui/lib/screenshot.dart
+++ b/dev/integration_tests/ui/lib/screenshot.dart
@@ -16,7 +16,7 @@ void main() {
 }
 
 class Toggler extends StatefulWidget {
-  const Toggler({Key key}) : super(key: key);
+  const Toggler({Key? key}) : super(key: key);
 
   @override
   State<Toggler> createState() => TogglerState();
diff --git a/dev/integration_tests/ui/pubspec.yaml b/dev/integration_tests/ui/pubspec.yaml
index c55e2e6e0d3..d18cab90f64 100644
--- a/dev/integration_tests/ui/pubspec.yaml
+++ b/dev/integration_tests/ui/pubspec.yaml
@@ -2,7 +2,7 @@ name: integration_ui
 description: Flutter non-plugin UI integration tests.
 
 environment:
-  sdk: ">=2.8.0 <3.0.0"
+  sdk: ">=2.12.0 <3.0.0"
 
 # The "image" dependency below seems to only be needed for test_driver/screenshot_test.dart
 # It can probably be removed, see the comment in that file.
diff --git a/dev/integration_tests/ui/test_driver/commands_debug_paint_test.dart b/dev/integration_tests/ui/test_driver/commands_debug_paint_test.dart
index 1bd6c7c3706..f5fbdf1b076 100644
--- a/dev/integration_tests/ui/test_driver/commands_debug_paint_test.dart
+++ b/dev/integration_tests/ui/test_driver/commands_debug_paint_test.dart
@@ -6,14 +6,14 @@ import 'package:flutter_driver/flutter_driver.dart';
 import 'package:test/test.dart' hide TypeMatcher, isInstanceOf;
 
 void main() {
-  FlutterDriver driver;
+  late FlutterDriver driver;
 
   setUpAll(() async {
     driver = await FlutterDriver.connect();
   });
 
   tearDownAll(() async {
-    await driver?.close();
+    await driver.close();
   });
 
   test('check that we are painting in debugPaintSize mode', () async {
diff --git a/dev/integration_tests/ui/test_driver/commands_none_test.dart b/dev/integration_tests/ui/test_driver/commands_none_test.dart
index e3fe9fa1530..dfdb903f5f1 100644
--- a/dev/integration_tests/ui/test_driver/commands_none_test.dart
+++ b/dev/integration_tests/ui/test_driver/commands_none_test.dart
@@ -6,14 +6,14 @@ import 'package:flutter_driver/flutter_driver.dart';
 import 'package:test/test.dart' hide TypeMatcher, isInstanceOf;
 
 void main() {
-  FlutterDriver driver;
+  late FlutterDriver driver;
 
   setUpAll(() async {
     driver = await FlutterDriver.connect();
   });
 
   tearDownAll(() async {
-    await driver?.close();
+    await driver.close();
   });
 
   test('check that we are in normal mode', () async {
diff --git a/dev/integration_tests/ui/test_driver/commands_performance_overlay_test.dart b/dev/integration_tests/ui/test_driver/commands_performance_overlay_test.dart
index fed70f3d07c..c4890552dcd 100644
--- a/dev/integration_tests/ui/test_driver/commands_performance_overlay_test.dart
+++ b/dev/integration_tests/ui/test_driver/commands_performance_overlay_test.dart
@@ -6,14 +6,14 @@ import 'package:flutter_driver/flutter_driver.dart';
 import 'package:test/test.dart' hide TypeMatcher, isInstanceOf;
 
 void main() {
-  FlutterDriver driver;
+  late FlutterDriver driver;
 
   setUpAll(() async {
     driver = await FlutterDriver.connect();
   });
 
   tearDownAll(() async {
-    await driver?.close();
+    await driver.close();
   });
 
   test('check that we are showing the performance overlay', () async {
diff --git a/dev/integration_tests/ui/test_driver/defines_test.dart b/dev/integration_tests/ui/test_driver/defines_test.dart
index a4b53182920..63665b884f8 100644
--- a/dev/integration_tests/ui/test_driver/defines_test.dart
+++ b/dev/integration_tests/ui/test_driver/defines_test.dart
@@ -6,7 +6,7 @@ import 'package:flutter_driver/flutter_driver.dart';
 import 'package:test/test.dart' hide TypeMatcher, isInstanceOf;
 
 void main() {
-  FlutterDriver driver;
+  late FlutterDriver driver;
 
   setUpAll(() async {
     driver = await FlutterDriver.connect();
diff --git a/dev/integration_tests/ui/test_driver/driver_test.dart b/dev/integration_tests/ui/test_driver/driver_test.dart
index 493dc8f51a0..8919b427aaf 100644
--- a/dev/integration_tests/ui/test_driver/driver_test.dart
+++ b/dev/integration_tests/ui/test_driver/driver_test.dart
@@ -11,7 +11,7 @@ import 'package:test/test.dart' hide TypeMatcher, isInstanceOf;
 void main() {
   group('FlutterDriver', () {
     final SerializableFinder presentText = find.text('present');
-    FlutterDriver driver;
+    late FlutterDriver driver;
 
     setUpAll(() async {
       driver = await FlutterDriver.connect();
diff --git a/dev/integration_tests/ui/test_driver/empty_test.dart b/dev/integration_tests/ui/test_driver/empty_test.dart
index d504a60fbdf..2daec600ff5 100644
--- a/dev/integration_tests/ui/test_driver/empty_test.dart
+++ b/dev/integration_tests/ui/test_driver/empty_test.dart
@@ -8,7 +8,7 @@ import 'package:test/test.dart' hide TypeMatcher, isInstanceOf;
 // Connect and disconnect from the empty app.
 void main() {
   group('FlutterDriver', () {
-    FlutterDriver driver;
+    late FlutterDriver driver;
 
     setUpAll(() async {
       driver = await FlutterDriver.connect();
diff --git a/dev/integration_tests/ui/test_driver/keyboard_resize_test.dart b/dev/integration_tests/ui/test_driver/keyboard_resize_test.dart
index 1e8eea75993..d224142114a 100644
--- a/dev/integration_tests/ui/test_driver/keyboard_resize_test.dart
+++ b/dev/integration_tests/ui/test_driver/keyboard_resize_test.dart
@@ -8,14 +8,14 @@ import 'package:test/test.dart' hide TypeMatcher, isInstanceOf;
 
 void main() {
   group('end-to-end test', () {
-    FlutterDriver driver;
+    late FlutterDriver driver;
 
     setUpAll(() async {
       driver = await FlutterDriver.connect();
     });
 
     tearDownAll(() async {
-      await driver?.close();
+      await driver.close();
     });
 
     test('Ensure keyboard dismissal resizes the view to original size', () async {
diff --git a/dev/integration_tests/ui/test_driver/keyboard_textfield_test.dart b/dev/integration_tests/ui/test_driver/keyboard_textfield_test.dart
index ee5a7d793a5..9eecafe04b2 100644
--- a/dev/integration_tests/ui/test_driver/keyboard_textfield_test.dart
+++ b/dev/integration_tests/ui/test_driver/keyboard_textfield_test.dart
@@ -8,14 +8,14 @@ import 'package:test/test.dart' hide TypeMatcher, isInstanceOf;
 
 void main() {
   group('end-to-end test', () {
-    FlutterDriver driver;
+    late FlutterDriver driver;
 
     setUpAll(() async {
       driver = await FlutterDriver.connect();
     });
 
     tearDownAll(() async {
-      await driver?.close();
+      await driver.close();
     });
 
     test('Textfield scrolls back into view after covered by keyboard', () async {
diff --git a/dev/integration_tests/ui/test_driver/license_check_test.dart b/dev/integration_tests/ui/test_driver/license_check_test.dart
index 3e1fce9a315..56f04f0af9f 100644
--- a/dev/integration_tests/ui/test_driver/license_check_test.dart
+++ b/dev/integration_tests/ui/test_driver/license_check_test.dart
@@ -20,7 +20,7 @@ void main() {
   final String license = licenseFile.readAsStringSync().split(newlineSplit).join(' ').trim();
 
   group('License file check', () {
-    FlutterDriver driver;
+    late FlutterDriver driver;
 
     setUpAll(() async {
       driver = await FlutterDriver.connect();
@@ -28,9 +28,7 @@ void main() {
     });
 
     tearDownAll(() async {
-      if (driver != null) {
-        await driver.close();
-      }
+      await driver.close();
     });
 
     test('flutter license', () async {
diff --git a/dev/integration_tests/ui/test_driver/route_test.dart b/dev/integration_tests/ui/test_driver/route_test.dart
index 7a8951417ea..6f1ecf53256 100644
--- a/dev/integration_tests/ui/test_driver/route_test.dart
+++ b/dev/integration_tests/ui/test_driver/route_test.dart
@@ -8,14 +8,14 @@ import 'package:test/test.dart' hide TypeMatcher, isInstanceOf;
 
 void main() {
   group('flutter run test --route', () {
-    FlutterDriver driver;
+    late FlutterDriver driver;
 
     setUpAll(() async {
       driver = await FlutterDriver.connect();
     });
 
     tearDownAll(() async {
-      await driver?.close();
+      await driver.close();
     });
 
     test('sanity check flutter drive --route', () async {
diff --git a/dev/integration_tests/ui/test_driver/screenshot_test.dart b/dev/integration_tests/ui/test_driver/screenshot_test.dart
index 456b3726bea..34618c18c48 100644
--- a/dev/integration_tests/ui/test_driver/screenshot_test.dart
+++ b/dev/integration_tests/ui/test_driver/screenshot_test.dart
@@ -15,7 +15,7 @@ import 'package:test/test.dart' hide TypeMatcher, isInstanceOf;
 
 void main() {
   group('FlutterDriver', () {
-    FlutterDriver driver;
+    late FlutterDriver driver;
 
     setUpAll(() async {
       driver = await FlutterDriver.connect();
@@ -32,18 +32,18 @@ void main() {
       await driver.waitFor(toggleBtn);
 
       bool cardsShouldBeVisible = false;
-      Image imageBefore = decodePng(await driver.screenshot());
+      Image? imageBefore = decodePng(await driver.screenshot());
       for (int i = 0; i < 10; i += 1) {
         await driver.tap(toggleBtn);
         cardsShouldBeVisible = !cardsShouldBeVisible;
-        final Image imageAfter = decodePng(await driver.screenshot());
+        final Image? imageAfter = decodePng(await driver.screenshot());
 
         if (cardsShouldBeVisible) {
-          expect(imageBefore.data, isNot(cardsAreVisible));
-          expect(imageAfter.data, cardsAreVisible);
+          expect(imageBefore?.data, isNot(cardsAreVisible));
+          expect(imageAfter?.data, cardsAreVisible);
         } else {
-          expect(imageBefore.data, cardsAreVisible);
-          expect(imageAfter.data, isNot(cardsAreVisible));
+          expect(imageBefore?.data, cardsAreVisible);
+          expect(imageAfter?.data, isNot(cardsAreVisible));
         }
 
         imageBefore = imageAfter;