diff --git a/aio/aio-builds-setup/dockerbuild/scripts-js/package.json b/aio/aio-builds-setup/dockerbuild/scripts-js/package.json
index 1f42dbc4eb..f9a7a54bd4 100644
--- a/aio/aio-builds-setup/dockerbuild/scripts-js/package.json
+++ b/aio/aio-builds-setup/dockerbuild/scripts-js/package.json
@@ -49,6 +49,6 @@
     "supertest": "^4.0.2",
     "tslint": "^6.1.3",
     "tslint-jasmine-noSkipOrFocus": "^1.0.9",
-    "typescript": "^4.0.2"
+    "typescript": "^4.1.2"
   }
 }
diff --git a/aio/aio-builds-setup/dockerbuild/scripts-js/yarn.lock b/aio/aio-builds-setup/dockerbuild/scripts-js/yarn.lock
index 01b93fcb31..f148e6b9a3 100644
--- a/aio/aio-builds-setup/dockerbuild/scripts-js/yarn.lock
+++ b/aio/aio-builds-setup/dockerbuild/scripts-js/yarn.lock
@@ -2563,10 +2563,10 @@ typedarray-to-buffer@^3.1.5:
   dependencies:
     is-typedarray "^1.0.0"
 
-typescript@^4.0.2:
-  version "4.0.2"
-  resolved "https://registry.yarnpkg.com/typescript/-/typescript-4.0.2.tgz#7ea7c88777c723c681e33bf7988be5d008d05ac2"
-  integrity sha512-e4ERvRV2wb+rRZ/IQeb3jm2VxBsirQLpQhdxplZ2MEzGvDkkMmPglecnNDfSUBivMjP93vRbngYYDQqQ/78bcQ==
+typescript@^4.1.2:
+  version "4.1.2"
+  resolved "https://registry.yarnpkg.com/typescript/-/typescript-4.1.2.tgz#6369ef22516fe5e10304aae5a5c4862db55380e9"
+  integrity sha512-thGloWsGH3SOxv1SoY7QojKi0tc+8FnOmiarEGMbd/lar7QOEd3hvlx3Fp5y6FlDUGl9L+pd4n2e+oToGMmhRQ==
 
 undefsafe@^2.0.2:
   version "2.0.2"
diff --git a/aio/src/app/custom-elements/elements-loader.spec.ts b/aio/src/app/custom-elements/elements-loader.spec.ts
index 48c188df1b..bdc0e5cc20 100644
--- a/aio/src/app/custom-elements/elements-loader.spec.ts
+++ b/aio/src/app/custom-elements/elements-loader.spec.ts
@@ -304,6 +304,6 @@ class FakeModuleFactory extends NgModuleFactory<any> {
 
 function returnPromisesFromSpy(spy: jasmine.Spy): Deferred[] {
   const deferreds: Deferred[] = [];
-  spy.and.callFake(() => new Promise((resolve, reject) => deferreds.push({resolve, reject})));
+  spy.and.callFake(() => new Promise<void>((resolve, reject) => deferreds.push({resolve, reject})));
   return deferreds;
 }
diff --git a/aio/yarn.lock b/aio/yarn.lock
index b95cd148f7..4c64e7f868 100644
--- a/aio/yarn.lock
+++ b/aio/yarn.lock
@@ -13658,7 +13658,7 @@ typedarray@^0.0.6:
   resolved "https://registry.yarnpkg.com/typedarray/-/typedarray-0.0.6.tgz#867ac74e3864187b1d3d47d996a78ec5c8830777"
   integrity sha1-hnrHTjhkGHsdPUfZlqeOxciDB3c=
 
-typescript@4.0.5:
+typescript@4.0.5, typescript@~4.0.2:
   version "4.0.5"
   resolved "https://registry.yarnpkg.com/typescript/-/typescript-4.0.5.tgz#ae9dddfd1069f1cb5beb3ef3b2170dd7c1332389"
   integrity sha512-ywmr/VrTVCmNTJ6iV2LwIrfG1P+lv6luD8sUJs+2eI9NLGigaN+nUQc13iHqisq7bra9lnmUSYqbJvegraBOPQ==
@@ -13668,11 +13668,6 @@ typescript@^3.2.2:
   resolved "https://registry.yarnpkg.com/typescript/-/typescript-3.7.5.tgz#0692e21f65fd4108b9330238aac11dd2e177a1ae"
   integrity sha512-/P5lkRXkWHNAbcJIiHPfRoKqyd7bsyCma1hZNUGfn20qm64T6ZBlrzprymeu918H+mB/0rIg2gGK/BXkhhYgBw==
 
-typescript@~4.0.2:
-  version "4.0.3"
-  resolved "https://registry.yarnpkg.com/typescript/-/typescript-4.0.3.tgz#153bbd468ef07725c1df9c77e8b453f8d36abba5"
-  integrity sha512-tEu6DGxGgRJPb/mVPIZ48e69xCn2yRmCgYmDugAVwmJ6o+0u1RI18eO7E7WBTLYLaEVVOhwQmcdhQHweux/WPg==
-
 ua-parser-js@0.7.21:
   version "0.7.21"
   resolved "https://registry.yarnpkg.com/ua-parser-js/-/ua-parser-js-0.7.21.tgz#853cf9ce93f642f67174273cc34565ae6f308777"
diff --git a/dev-infra/caretaker/check/base.ts b/dev-infra/caretaker/check/base.ts
index 338688a4c4..746c15cead 100644
--- a/dev-infra/caretaker/check/base.ts
+++ b/dev-infra/caretaker/check/base.ts
@@ -18,8 +18,8 @@ export abstract class BaseModule<Data> {
       protected git: GitClient, protected config: NgDevConfig<{caretaker: CaretakerConfig}>) {}
 
   /** Asyncronously retrieve data for the module. */
-  protected abstract async retrieveData(): Promise<Data>;
+  protected abstract retrieveData(): Promise<Data>;
 
   /** Print the information discovered for the module to the terminal. */
-  abstract async printToTerminal(): Promise<void>;
+  abstract printToTerminal(): Promise<void>;
 }
diff --git a/modules/benchmarks/src/expanding_rows/benchmark.ts b/modules/benchmarks/src/expanding_rows/benchmark.ts
index a2ec65c8a2..d1194447e5 100644
--- a/modules/benchmarks/src/expanding_rows/benchmark.ts
+++ b/modules/benchmarks/src/expanding_rows/benchmark.ts
@@ -83,7 +83,7 @@ export async function execTimed(description: string, func: () => Promise<void>)
 }
 
 export async function nextTick(delay = 1) {
-  return new Promise((res, rej) => {
+  return new Promise<void>((res, rej) => {
     setTimeout(() => {
       res();
     }, delay);
diff --git a/package.json b/package.json
index 2b30de950f..4c4fe0ef19 100644
--- a/package.json
+++ b/package.json
@@ -150,7 +150,7 @@
     "tsickle": "0.38.1",
     "tslib": "^2.0.0",
     "tslint": "6.1.3",
-    "typescript": "~4.0.2",
+    "typescript": "~4.1.2",
     "xhr2": "0.2.0",
     "yaml": "^1.10.0",
     "yargs": "^16.1.1"
diff --git a/packages/animations/browser/src/render/transition_animation_engine.ts b/packages/animations/browser/src/render/transition_animation_engine.ts
index a6e23086d5..79703bc234 100644
--- a/packages/animations/browser/src/render/transition_animation_engine.ts
+++ b/packages/animations/browser/src/render/transition_animation_engine.ts
@@ -810,7 +810,7 @@ export class TransitionAnimationEngine {
   }
 
   whenRenderingDone(): Promise<any> {
-    return new Promise(resolve => {
+    return new Promise<void>(resolve => {
       if (this.players.length) {
         return optimizeGroupPlayer(this.players).onDone(() => resolve());
       } else {
diff --git a/packages/bazel/package.json b/packages/bazel/package.json
index 798b8b2c7c..aa65c45fad 100644
--- a/packages/bazel/package.json
+++ b/packages/bazel/package.json
@@ -28,7 +28,7 @@
     "@angular/compiler-cli": "0.0.0-PLACEHOLDER",
     "@bazel/typescript": ">=1.0.0",
     "terser": "^4.3.1",
-    "typescript": ">=4.0 <4.1",
+    "typescript": ">=4.0 <4.2",
     "rollup": ">=1.20.0",
     "rollup-plugin-commonjs": ">=9.0.0",
     "rollup-plugin-node-resolve": ">=4.2.0",
diff --git a/packages/benchpress/src/common_options.ts b/packages/benchpress/src/common_options.ts
index e923714567..1186b5edea 100644
--- a/packages/benchpress/src/common_options.ts
+++ b/packages/benchpress/src/common_options.ts
@@ -43,7 +43,7 @@ export class Options {
 }
 
 function writeFile(filename: string, content: string): Promise<any> {
-  return new Promise(function(resolve, reject) {
+  return new Promise<void>(function(resolve, reject) {
     fs.writeFile(filename, content, (error) => {
       if (error) {
         reject(error);
diff --git a/packages/compiler-cli/ngcc/src/host/commonjs_umd_utils.ts b/packages/compiler-cli/ngcc/src/host/commonjs_umd_utils.ts
index b762eafdec..2f20337b5e 100644
--- a/packages/compiler-cli/ngcc/src/host/commonjs_umd_utils.ts
+++ b/packages/compiler-cli/ngcc/src/host/commonjs_umd_utils.ts
@@ -78,7 +78,7 @@ export function findNamespaceOfIdentifier(id: ts.Identifier): ts.Identifier|null
 export function findRequireCallReference(id: ts.Identifier, checker: ts.TypeChecker): RequireCall|
     null {
   const symbol = checker.getSymbolAtLocation(id) || null;
-  const declaration = symbol && symbol.valueDeclaration;
+  const declaration = symbol?.valueDeclaration ?? symbol?.declarations?.[0];
   const initializer =
       declaration && ts.isVariableDeclaration(declaration) && declaration.initializer || null;
   return initializer && isRequireCall(initializer) ? initializer : null;
diff --git a/packages/compiler-cli/package.json b/packages/compiler-cli/package.json
index 076066f2df..d47c5f2da5 100644
--- a/packages/compiler-cli/package.json
+++ b/packages/compiler-cli/package.json
@@ -29,7 +29,7 @@
   },
   "peerDependencies": {
     "@angular/compiler": "0.0.0-PLACEHOLDER",
-    "typescript": ">=4.0 <4.1"
+    "typescript": ">=4.0 <4.2"
   },
   "engines": {
     "node": ">=10.0"
diff --git a/packages/compiler-cli/src/ngtsc/testing/src/utils.ts b/packages/compiler-cli/src/ngtsc/testing/src/utils.ts
index 7fe09b6686..13fe87a560 100644
--- a/packages/compiler-cli/src/ngtsc/testing/src/utils.ts
+++ b/packages/compiler-cli/src/ngtsc/testing/src/utils.ts
@@ -126,9 +126,9 @@ enum TsStructureIsReused {
   Completely = 2,
 }
 
-export function expectCompleteReuse(oldProgram: ts.Program): void {
+export function expectCompleteReuse(program: ts.Program): void {
   // Assert complete reuse using TypeScript's private API.
-  expect((oldProgram as any).structureIsReused)
+  expect((program as any).structureIsReused)
       .toBe(TsStructureIsReused.Completely, COMPLETE_REUSE_FAILURE_MESSAGE);
 }
 
diff --git a/packages/compiler-cli/src/ngtsc/typecheck/test/program_spec.ts b/packages/compiler-cli/src/ngtsc/typecheck/test/program_spec.ts
index 601808d55e..e1ae444dc2 100644
--- a/packages/compiler-cli/src/ngtsc/typecheck/test/program_spec.ts
+++ b/packages/compiler-cli/src/ngtsc/typecheck/test/program_spec.ts
@@ -44,7 +44,7 @@ runInEachFileSystem(() => {
       programStrategy.updateFiles(
           new Map([[typecheckPath, 'export const VERSION = 2;']]), UpdateMode.Complete);
 
-      expectCompleteReuse(program);
+      expectCompleteReuse(programStrategy.getProgram());
     });
 
     it('should have complete reuse if no structural changes are made to input files', () => {
@@ -56,7 +56,7 @@ runInEachFileSystem(() => {
       programStrategy.updateFiles(
           new Map([[mainPath, 'export const STILL_NOT_A_COMPONENT = true;']]), UpdateMode.Complete);
 
-      expectCompleteReuse(program);
+      expectCompleteReuse(programStrategy.getProgram());
     });
   });
 });
diff --git a/packages/compiler-cli/src/perform_watch.ts b/packages/compiler-cli/src/perform_watch.ts
index 245d82eb91..7002bbe59a 100644
--- a/packages/compiler-cli/src/perform_watch.ts
+++ b/packages/compiler-cli/src/perform_watch.ts
@@ -127,7 +127,7 @@ export function performWatchCompilation(host: PerformWatchHost):
 
   // Watch basePath, ignoring .dotfiles
   let resolveReadyPromise: () => void;
-  const readyPromise = new Promise(resolve => resolveReadyPromise = resolve);
+  const readyPromise = new Promise<void>(resolve => resolveReadyPromise = resolve);
   // Note: ! is ok as options are filled after the first compilation
   // Note: ! is ok as resolvedReadyPromise is filled by the previous call
   const fileWatcher =
diff --git a/packages/compiler-cli/src/transformers/program.ts b/packages/compiler-cli/src/transformers/program.ts
index b7abbfc535..f82477b43a 100644
--- a/packages/compiler-cli/src/transformers/program.ts
+++ b/packages/compiler-cli/src/transformers/program.ts
@@ -48,6 +48,17 @@ const LOWER_FIELDS = ['useValue', 'useFactory', 'data', 'id', 'loadChildren'];
  */
 const R3_LOWER_FIELDS = [...LOWER_FIELDS, 'providers', 'imports', 'exports'];
 
+/**
+ * Installs a handler for testing purposes to allow inspection of the temporary program.
+ */
+let tempProgramHandlerForTest: ((program: ts.Program) => void)|null = null;
+export function setTempProgramHandlerForTest(handler: (program: ts.Program) => void): void {
+  tempProgramHandlerForTest = handler;
+}
+export function resetTempProgramHandlerForTest(): void {
+  tempProgramHandlerForTest = null;
+}
+
 const emptyModules: NgAnalyzedModules = {
   ngModules: [],
   ngModuleByPipeOrDirective: new Map(),
@@ -618,6 +629,9 @@ class AngularCompilerProgram implements Program {
     }
 
     const tmpProgram = ts.createProgram(rootNames, this.options, this.hostAdapter, oldTsProgram);
+    if (tempProgramHandlerForTest !== null) {
+      tempProgramHandlerForTest(tmpProgram);
+    }
     const sourceFiles: string[] = [];
     const tsFiles: string[] = [];
     tmpProgram.getSourceFiles().forEach(sf => {
diff --git a/packages/compiler-cli/test/ngc_spec.ts b/packages/compiler-cli/test/ngc_spec.ts
index 0e35c3ee8c..0f8cd65c1a 100644
--- a/packages/compiler-cli/test/ngc_spec.ts
+++ b/packages/compiler-cli/test/ngc_spec.ts
@@ -1671,7 +1671,7 @@ describe('ngc transformer command-line', () => {
         const config = readCommandLineAndConfiguration(['-p', basePath]);
         const compile = watchMode(config.project, config.options, errorSpy);
 
-        return new Promise(resolve => {
+        return new Promise<void>(resolve => {
           compile.ready(() => {
             cb();
 
diff --git a/packages/compiler-cli/test/ngtsc/template_typecheck_spec.ts b/packages/compiler-cli/test/ngtsc/template_typecheck_spec.ts
index def7a8bf16..2125d09409 100644
--- a/packages/compiler-cli/test/ngtsc/template_typecheck_spec.ts
+++ b/packages/compiler-cli/test/ngtsc/template_typecheck_spec.ts
@@ -358,7 +358,7 @@ export declare class AnimationEvent {
 
           @Component({
             selector: 'test',
-            template: '<div dir [foo]="invalid && 1"></div>',
+            template: '<div dir [foo]="!!invalid"></div>',
           })
           class TestCmp {}
 
@@ -379,7 +379,7 @@ export declare class AnimationEvent {
 
         const diags = env.driveDiagnostics();
         expect(diags.length).toBe(2);
-        expect(diags[0].messageText).toEqual(`Type 'number' is not assignable to type 'string'.`);
+        expect(diags[0].messageText).toEqual(`Type 'boolean' is not assignable to type 'string'.`);
         expect(diags[1].messageText)
             .toEqual(`Property 'invalid' does not exist on type 'TestCmp'.`);
       });
@@ -389,7 +389,7 @@ export declare class AnimationEvent {
 
         const diags = env.driveDiagnostics();
         expect(diags.length).toBe(2);
-        expect(diags[0].messageText).toEqual(`Type 'number' is not assignable to type 'string'.`);
+        expect(diags[0].messageText).toEqual(`Type 'boolean' is not assignable to type 'string'.`);
         expect(diags[1].messageText)
             .toEqual(`Property 'invalid' does not exist on type 'TestCmp'.`);
       });
@@ -411,15 +411,15 @@ export declare class AnimationEvent {
 
           @Component({
             selector: 'test',
-            template: '<div dir [foo]="invalid && nullable"></div>',
+            template: '<div dir [foo]="!!invalid && nullable"></div>',
           })
           class TestCmp {
-            nullable: string | null | undefined;
+            nullable: boolean | null | undefined;
           }
 
           @Directive({selector: '[dir]'})
           class TestDir {
-            @Input() foo: string;
+            @Input() foo: boolean;
           }
 
           @NgModule({
@@ -436,7 +436,7 @@ export declare class AnimationEvent {
         const diags = env.driveDiagnostics();
         expect(diags.length).toBe(2);
         expect((diags[0].messageText as ts.DiagnosticMessageChain).messageText)
-            .toEqual(`Type 'string | null | undefined' is not assignable to type 'string'.`);
+            .toEqual(`Type 'boolean | null | undefined' is not assignable to type 'boolean'.`);
         expect(diags[1].messageText)
             .toEqual(`Property 'invalid' does not exist on type 'TestCmp'.`);
       });
@@ -448,7 +448,7 @@ export declare class AnimationEvent {
            const diags = env.driveDiagnostics();
            expect(diags.length).toBe(2);
            expect((diags[0].messageText as ts.DiagnosticMessageChain).messageText)
-               .toEqual(`Type 'string | null | undefined' is not assignable to type 'string'.`);
+               .toEqual(`Type 'boolean | null | undefined' is not assignable to type 'boolean'.`);
            expect(diags[1].messageText)
                .toEqual(`Property 'invalid' does not exist on type 'TestCmp'.`);
          });
@@ -470,15 +470,15 @@ export declare class AnimationEvent {
 
           @Component({
             selector: 'test',
-            template: '<div dir [foo]="invalid && user?.name"></div>',
+            template: '<div dir [foo]="!!invalid && user?.isMember"></div>',
           })
           class TestCmp {
-            user?: {name: string};
+            user?: {isMember: boolean};
           }
 
           @Directive({selector: '[dir]'})
           class TestDir {
-            @Input() foo: string;
+            @Input() foo: boolean;
           }
 
           @NgModule({
@@ -499,7 +499,7 @@ export declare class AnimationEvent {
         const diags = env.driveDiagnostics();
         expect(diags.length).toBe(2);
         expect((diags[0].messageText as ts.DiagnosticMessageChain).messageText)
-            .toEqual(`Type 'string | undefined' is not assignable to type 'string'.`);
+            .toEqual(`Type 'boolean | undefined' is not assignable to type 'boolean'.`);
         expect(diags[1].messageText)
             .toEqual(`Property 'invalid' does not exist on type 'TestCmp'.`);
       });
@@ -511,7 +511,7 @@ export declare class AnimationEvent {
            const diags = env.driveDiagnostics();
            expect(diags.length).toBe(2);
            expect((diags[0].messageText as ts.DiagnosticMessageChain).messageText)
-               .toEqual(`Type 'string | undefined' is not assignable to type 'string'.`);
+               .toEqual(`Type 'boolean | undefined' is not assignable to type 'boolean'.`);
            expect(diags[1].messageText)
                .toEqual(`Property 'invalid' does not exist on type 'TestCmp'.`);
          });
@@ -2325,7 +2325,8 @@ export declare class AnimationEvent {
         env.write('other.ts', `export const VERSION = 2;`);
         env.driveMain();
 
-        expectCompleteReuse(firstProgram);
+        expectCompleteReuse(env.getTsProgram());
+        expectCompleteReuse(env.getReuseTsProgram());
       });
     });
   });
diff --git a/packages/compiler-cli/test/transformers/program_spec.ts b/packages/compiler-cli/test/transformers/program_spec.ts
index 683612d723..c2f4588b17 100644
--- a/packages/compiler-cli/test/transformers/program_spec.ts
+++ b/packages/compiler-cli/test/transformers/program_spec.ts
@@ -13,7 +13,7 @@ import * as ts from 'typescript';
 
 import {formatDiagnostics} from '../../src/perform_compile';
 import {CompilerHost, EmitFlags, LazyRoute} from '../../src/transformers/api';
-import {createSrcToOutPathMapper} from '../../src/transformers/program';
+import {createSrcToOutPathMapper, resetTempProgramHandlerForTest, setTempProgramHandlerForTest} from '../../src/transformers/program';
 import {StructureIsReused, tsStructureIsReused} from '../../src/transformers/util';
 import {expectNoDiagnosticsInProgram, setup, stripAnsi, TestSupport} from '../test_support';
 
@@ -297,6 +297,17 @@ describe('ng program', () => {
     describe(
         'verify that program structure is reused within tsc in order to speed up incremental compilation',
         () => {
+          afterEach(resetTempProgramHandlerForTest);
+
+          function captureStructureReuse(compile: () => void): StructureIsReused|null {
+            let structureReuse: StructureIsReused|null = null;
+            setTempProgramHandlerForTest(program => {
+              structureReuse = tsStructureIsReused(program);
+            });
+            compile();
+            return structureReuse;
+          }
+
           it('should reuse the old ts program completely if nothing changed', () => {
             testSupport.writeFiles({'src/index.ts': createModuleAndCompSource('main')});
             const host = createWatchModeHost();
@@ -304,8 +315,9 @@ describe('ng program', () => {
             // and therefore changes the structure again
             const p1 = compile(undefined, undefined, undefined, host).program;
             const p2 = compile(p1, undefined, undefined, host).program;
-            compile(p2, undefined, undefined, host);
-            expect(tsStructureIsReused(p2.getTsProgram())).toBe(StructureIsReused.Completely);
+            const structureReuse =
+                captureStructureReuse(() => compile(p2, undefined, undefined, host));
+            expect(structureReuse).toBe(StructureIsReused.Completely);
           });
 
           it('should reuse the old ts program completely if a template or a ts file changed',
@@ -328,8 +340,9 @@ describe('ng program', () => {
                  'src/main.html': `Another template`,
                  'src/util.ts': `export const x = 2`,
                });
-               compile(p2, undefined, undefined, host);
-               expect(tsStructureIsReused(p2.getTsProgram())).toBe(StructureIsReused.Completely);
+               const structureReuse =
+                   captureStructureReuse(() => compile(p2, undefined, undefined, host));
+               expect(structureReuse).toBe(StructureIsReused.Completely);
              });
 
           it('should not reuse the old ts program if an import changed', () => {
@@ -348,8 +361,9 @@ describe('ng program', () => {
             const p2 = compile(p1, undefined, undefined, host).program;
             testSupport.writeFiles(
                 {'src/util.ts': `import {Injectable} from '@angular/core'; export const x = 1;`});
-            compile(p2, undefined, undefined, host);
-            expect(tsStructureIsReused(p2.getTsProgram())).toBe(StructureIsReused.SafeModules);
+            const structureReuse =
+                captureStructureReuse(() => compile(p2, undefined, undefined, host));
+            expect(structureReuse).toBe(StructureIsReused.SafeModules);
           });
         });
   });
diff --git a/packages/compiler/test/expression_parser/parser_spec.ts b/packages/compiler/test/expression_parser/parser_spec.ts
index 0bc5323920..52db296380 100644
--- a/packages/compiler/test/expression_parser/parser_spec.ts
+++ b/packages/compiler/test/expression_parser/parser_spec.ts
@@ -1048,7 +1048,7 @@ function expectParseTemplateBindingsError(attribute: string, error: string) {
 function _parseTemplateBindings(attribute: string, templateUrl: string) {
   const match = attribute.match(/^\*(.+)="(.*)"$/);
   expect(match).toBeTruthy(`failed to extract key and value from ${attribute}`);
-  const [_, key, value] = match;
+  const [_, key, value] = match!;
   const absKeyOffset = 1;  // skip the * prefix
   const absValueOffset = attribute.indexOf('=') + '="'.length;
   const parser = createParser();
diff --git a/packages/platform-server/test/integration_spec.ts b/packages/platform-server/test/integration_spec.ts
index 34740d10ac..11245bf6cb 100644
--- a/packages/platform-server/test/integration_spec.ts
+++ b/packages/platform-server/test/integration_spec.ts
@@ -53,7 +53,7 @@ function getMetaRenderHook(doc: any) {
 function getAsyncTitleRenderHook(doc: any) {
   return () => {
     // Async set the title as part of the render hook.
-    return new Promise(resolve => {
+    return new Promise<void>(resolve => {
       setTimeout(() => {
         doc.title = 'AsyncRenderHook';
         resolve();
@@ -64,7 +64,7 @@ function getAsyncTitleRenderHook(doc: any) {
 
 function asyncRejectRenderHook() {
   return () => {
-    return new Promise((_resolve, reject) => {
+    return new Promise<void>((_resolve, reject) => {
       setTimeout(() => {
         reject('reject');
       });
diff --git a/packages/upgrade/src/common/src/util.ts b/packages/upgrade/src/common/src/util.ts
index 982b1365da..1c772f9bb4 100644
--- a/packages/upgrade/src/common/src/util.ts
+++ b/packages/upgrade/src/common/src/util.ts
@@ -97,7 +97,7 @@ export function validateInjectionKey(
 export class Deferred<R> {
   promise: Promise<R>;
   // TODO(issue/24571): remove '!'.
-  resolve!: (value?: R|PromiseLike<R>) => void;
+  resolve!: (value: R|PromiseLike<R>) => void;
   // TODO(issue/24571): remove '!'.
   reject!: (error?: any) => void;
 
diff --git a/packages/upgrade/src/dynamic/src/upgrade_adapter.ts b/packages/upgrade/src/dynamic/src/upgrade_adapter.ts
index 1e39bd7f9c..bbb304e494 100644
--- a/packages/upgrade/src/dynamic/src/upgrade_adapter.ts
+++ b/packages/upgrade/src/dynamic/src/upgrade_adapter.ts
@@ -396,7 +396,7 @@ export class UpgradeAdapter {
     this.ngZone.run(() => {
       bootstrap(element, [this.ng1Module.name], config!);
     });
-    const ng1BootstrapPromise = new Promise((resolve) => {
+    const ng1BootstrapPromise = new Promise<void>((resolve) => {
       if (windowAngular.resumeBootstrap) {
         const originalResumeBootstrap: () => void = windowAngular.resumeBootstrap;
         windowAngular.resumeBootstrap = function() {
diff --git a/packages/zone.js/package.json b/packages/zone.js/package.json
index 67f2b6e96d..960360682e 100644
--- a/packages/zone.js/package.json
+++ b/packages/zone.js/package.json
@@ -19,7 +19,7 @@
     "mocha": "^3.1.2",
     "mock-require": "3.0.3",
     "promises-aplus-tests": "^2.1.2",
-    "typescript": "4.0.2"
+    "typescript": "4.1.2"
   },
   "scripts": {
     "closuretest": "./scripts/closure/closure_compiler.sh",
diff --git a/packages/zone.js/test/jasmine-patch.spec.ts b/packages/zone.js/test/jasmine-patch.spec.ts
index 375f63ca1b..6091f7a50e 100644
--- a/packages/zone.js/test/jasmine-patch.spec.ts
+++ b/packages/zone.js/test/jasmine-patch.spec.ts
@@ -65,7 +65,7 @@ ifEnvSupports(supportJasmineSpec, () => {
     });
 
     it('should wait for promise to resolve', () => {
-      return new Promise((res, _) => {
+      return new Promise<void>((res, _) => {
         setTimeout(() => {
           log.push('resolved');
           res();
diff --git a/packages/zone.js/test/mocha-patch.spec.ts b/packages/zone.js/test/mocha-patch.spec.ts
index 7195eb06c0..9c32a61fca 100644
--- a/packages/zone.js/test/mocha-patch.spec.ts
+++ b/packages/zone.js/test/mocha-patch.spec.ts
@@ -103,7 +103,7 @@ ifEnvSupports('Mocha', function() {
     });
 
     it('should wait for promise to resolve', () => {
-      return new Promise((res, _) => {
+      return new Promise<void>((res, _) => {
         setTimeout(() => {
           log.push('resolved');
           res();
diff --git a/packages/zone.js/test/typings/package.json b/packages/zone.js/test/typings/package.json
index cb87d67ac1..76163fbb18 100644
--- a/packages/zone.js/test/typings/package.json
+++ b/packages/zone.js/test/typings/package.json
@@ -14,6 +14,6 @@
     "zone.js": "file:../../../../dist/bin/packages/zone.js/npm_package"
   },
   "devDependencies": {
-    "typescript": "~4.0.2"
+    "typescript": "~4.1.2"
   }
 }
diff --git a/packages/zone.js/test/zone-spec/async-test.spec.ts b/packages/zone.js/test/zone-spec/async-test.spec.ts
index 26c4ac0bd9..90e8be4980 100644
--- a/packages/zone.js/test/zone-spec/async-test.spec.ts
+++ b/packages/zone.js/test/zone-spec/async-test.spec.ts
@@ -98,7 +98,7 @@ describe('AsyncTestZoneSpec', function() {
     const atz = Zone.current.fork(testZoneSpec);
 
     atz.run(function() {
-      new Promise((resolve) => {
+      new Promise<void>((resolve) => {
         setTimeout(() => {
           resolve();
         }, 10);
diff --git a/packages/zone.js/test/zone-spec/fake-async-test.spec.ts b/packages/zone.js/test/zone-spec/fake-async-test.spec.ts
index 1d9436770c..22724223a2 100644
--- a/packages/zone.js/test/zone-spec/fake-async-test.spec.ts
+++ b/packages/zone.js/test/zone-spec/fake-async-test.spec.ts
@@ -942,7 +942,7 @@ describe('FakeAsyncTestZoneSpec', () => {
     });
 
     it('should wait for promise to resolve', () => {
-      return new Promise((res, _) => {
+      return new Promise<void>((res, _) => {
         setTimeout(() => {
           log.push('resolved');
           res();
diff --git a/packages/zone.js/yarn.lock b/packages/zone.js/yarn.lock
index a794853648..8ef9211599 100644
--- a/packages/zone.js/yarn.lock
+++ b/packages/zone.js/yarn.lock
@@ -3786,10 +3786,10 @@ typedarray-to-buffer@^3.1.5:
   dependencies:
     is-typedarray "^1.0.0"
 
-typescript@4.0.2:
-  version "4.0.2"
-  resolved "https://registry.yarnpkg.com/typescript/-/typescript-4.0.2.tgz#7ea7c88777c723c681e33bf7988be5d008d05ac2"
-  integrity sha512-e4ERvRV2wb+rRZ/IQeb3jm2VxBsirQLpQhdxplZ2MEzGvDkkMmPglecnNDfSUBivMjP93vRbngYYDQqQ/78bcQ==
+typescript@4.1.2:
+  version "4.1.2"
+  resolved "https://registry.yarnpkg.com/typescript/-/typescript-4.1.2.tgz#6369ef22516fe5e10304aae5a5c4862db55380e9"
+  integrity sha512-thGloWsGH3SOxv1SoY7QojKi0tc+8FnOmiarEGMbd/lar7QOEd3hvlx3Fp5y6FlDUGl9L+pd4n2e+oToGMmhRQ==
 
 underscore@~1.8.3:
   version "1.8.3"
diff --git a/tools/ts-api-guardian/package.json b/tools/ts-api-guardian/package.json
index 4df0b9840e..236d90b550 100644
--- a/tools/ts-api-guardian/package.json
+++ b/tools/ts-api-guardian/package.json
@@ -33,7 +33,7 @@
     "chai": "^4.1.2",
     "jasmine": "^3.1.0",
     "source-map-support": "^0.5.9",
-    "typescript": "4.0.2"
+    "typescript": "4.1.2"
   },
   "repository": {},
   "keywords": [
@@ -51,4 +51,4 @@
     "url": "https://github.com/angular/angular/issues"
   },
   "homepage": "https://github.com/angular/angular/tools/ts-api-guardian"
-}
\ No newline at end of file
+}
diff --git a/yarn.lock b/yarn.lock
index 698f3ef441..be08369a4f 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -15621,10 +15621,10 @@ typescript@~3.7.2:
   resolved "https://registry.yarnpkg.com/typescript/-/typescript-3.7.5.tgz#0692e21f65fd4108b9330238aac11dd2e177a1ae"
   integrity sha512-/P5lkRXkWHNAbcJIiHPfRoKqyd7bsyCma1hZNUGfn20qm64T6ZBlrzprymeu918H+mB/0rIg2gGK/BXkhhYgBw==
 
-typescript@~4.0.2:
-  version "4.0.2"
-  resolved "https://registry.yarnpkg.com/typescript/-/typescript-4.0.2.tgz#7ea7c88777c723c681e33bf7988be5d008d05ac2"
-  integrity sha512-e4ERvRV2wb+rRZ/IQeb3jm2VxBsirQLpQhdxplZ2MEzGvDkkMmPglecnNDfSUBivMjP93vRbngYYDQqQ/78bcQ==
+typescript@~4.1.2:
+  version "4.1.2"
+  resolved "https://registry.yarnpkg.com/typescript/-/typescript-4.1.2.tgz#6369ef22516fe5e10304aae5a5c4862db55380e9"
+  integrity sha512-thGloWsGH3SOxv1SoY7QojKi0tc+8FnOmiarEGMbd/lar7QOEd3hvlx3Fp5y6FlDUGl9L+pd4n2e+oToGMmhRQ==
 
 uglify-js@^1.3.3:
   version "1.3.5"