diff --git a/integration/cli-hello-world-ivy-i18n/src/tsconfig.legacy.json b/integration/cli-hello-world-ivy-i18n/src/tsconfig.legacy.json
index 2c34ebff0d..3bf6947e21 100644
--- a/integration/cli-hello-world-ivy-i18n/src/tsconfig.legacy.json
+++ b/integration/cli-hello-world-ivy-i18n/src/tsconfig.legacy.json
@@ -2,6 +2,6 @@
   "extends": "./tsconfig.app.json",
   "angularCompilerOptions": {
     "enableIvy": true,
-    "i18nLegacyMessageIdFormat": "xlf"
+    "i18nInFormat": "xlf"
   }
 }
diff --git a/packages/compiler-cli/src/main.ts b/packages/compiler-cli/src/main.ts
index 047b620738..aad3add832 100644
--- a/packages/compiler-cli/src/main.ts
+++ b/packages/compiler-cli/src/main.ts
@@ -32,7 +32,6 @@ export function main(
   if (configErrors.length) {
     return reportErrorsAndExit(configErrors, /*options*/ undefined, consoleError);
   }
-  warnForDeprecatedOptions(options);
   if (watch) {
     const result = watchMode(project, options, consoleError);
     return reportErrorsAndExit(result.firstCompileResult, options, consoleError);
@@ -227,14 +226,6 @@ export function watchMode(
   }, options, options => createEmitCallback(options)));
 }
 
-function warnForDeprecatedOptions(options: api.CompilerOptions) {
-  if (options.i18nLegacyMessageIdFormat !== undefined) {
-    console.warn(
-        'The `i18nLegacyMessageIdFormat` option is deprecated.\n' +
-        'Migrate your legacy translation files to the new `$localize` message id format and remove this option.');
-  }
-}
-
 // CLI entry point
 if (require.main === module) {
   const args = process.argv.slice(2);
diff --git a/packages/compiler-cli/src/ngtsc/program.ts b/packages/compiler-cli/src/ngtsc/program.ts
index 19126f8b05..672a7a1fdc 100644
--- a/packages/compiler-cli/src/ngtsc/program.ts
+++ b/packages/compiler-cli/src/ngtsc/program.ts
@@ -509,7 +509,7 @@ export class NgtscProgram implements api.Program {
           this.reflector, evaluator, metaRegistry, this.metaReader !, scopeReader, scopeRegistry,
           this.isCore, this.resourceManager, this.rootDirs,
           this.options.preserveWhitespaces || false, this.options.i18nUseExternalIds !== false,
-          this.options.i18nLegacyMessageIdFormat || '', this.moduleResolver, this.cycleAnalyzer,
+          this.getI18nLegacyMessageFormat(), this.moduleResolver, this.cycleAnalyzer,
           this.refEmitter, this.defaultImportTracker, this.incrementalState),
       new DirectiveDecoratorHandler(
           this.reflector, evaluator, metaRegistry, this.defaultImportTracker, this.isCore),
@@ -529,6 +529,11 @@ export class NgtscProgram implements api.Program {
         this.sourceToFactorySymbols, scopeRegistry);
   }
 
+  private getI18nLegacyMessageFormat(): string {
+    return this.options.enableI18nLegacyMessageIdFormat !== false && this.options.i18nInFormat ||
+        '';
+  }
+
   private get reflector(): TypeScriptReflectionHost {
     if (this._reflector === undefined) {
       this._reflector = new TypeScriptReflectionHost(this.tsProgram.getTypeChecker());
diff --git a/packages/compiler-cli/src/transformers/api.ts b/packages/compiler-cli/src/transformers/api.ts
index 4d30349b7c..45cc6ae770 100644
--- a/packages/compiler-cli/src/transformers/api.ts
+++ b/packages/compiler-cli/src/transformers/api.ts
@@ -162,17 +162,16 @@ export interface CompilerOptions extends ts.CompilerOptions {
   i18nUseExternalIds?: boolean;
 
   /**
-   * Render `$localize` message ids with the specified legacy format (xlf, xlf2 or xmb).
+   * Render `$localize` message ids with the legacy format (xlf, xlf2 or xmb) specified in
+   * `i18nInFormat`.
+   *
+   * This is only active if we are building with `enableIvy: true` and a valid
+   * `i18nInFormat` has been provided. The default value for now is `true`.
    *
    * Use this option when use are using the `$localize` based localization messages but
    * have not migrated the translation files to use the new `$localize` message id format.
-   *
-   * @deprecated
-   * `i18nLegacyMessageIdFormat` should only be used while migrating from legacy message id
-   * formatted translation files and will be removed at the same time as ViewEngine support is
-   * removed.
    */
-  i18nLegacyMessageIdFormat?: string;
+  enableI18nLegacyMessageIdFormat?: boolean;
 
   // Whether to remove blank text nodes from compiled templates. It is `false` by default starting
   // from Angular 6.
diff --git a/packages/compiler-cli/test/ngtsc/ngtsc_spec.ts b/packages/compiler-cli/test/ngtsc/ngtsc_spec.ts
index b4b720ed14..a91c8abf49 100644
--- a/packages/compiler-cli/test/ngtsc/ngtsc_spec.ts
+++ b/packages/compiler-cli/test/ngtsc/ngtsc_spec.ts
@@ -2052,60 +2052,79 @@ runInEachFileSystem(os => {
       expect(jsContents).not.toContain('MSG_EXTERNAL_');
     });
 
-    it('should render legacy id when i18nLegacyMessageIdFormat config is set to xlf', () => {
-      env.tsconfig({i18nLegacyMessageIdFormat: 'xlf'});
-      env.write(`test.ts`, `
+    it('should render legacy id when `enableI18nLegacyMessageIdFormat` is not false and `i18nInFormat` is set to "xlf"',
+       () => {
+         env.tsconfig({i18nInFormat: 'xlf'});
+         env.write(`test.ts`, `
         import {Component} from '@angular/core';
         @Component({
           selector: 'test',
           template: '<div i18n>Some text</div>'
         })
         class FooCmp {}`);
-      env.driveMain();
-      const jsContents = env.getContents('test.js');
-      expect(jsContents).toContain(':@@5dbba0a3da8dff890e20cf76eb075d58900fbcd3:Some text');
-    });
+         env.driveMain();
+         const jsContents = env.getContents('test.js');
+         expect(jsContents).toContain(':@@5dbba0a3da8dff890e20cf76eb075d58900fbcd3:Some text');
+       });
 
-    it('should render legacy id when i18nLegacyMessageIdFormat config is set to xlf2', () => {
-      env.tsconfig({i18nLegacyMessageIdFormat: 'xlf2'});
-      env.write(`test.ts`, `
+    it('should render legacy id when `enableI18nLegacyMessageIdFormat` is not false and `i18nInFormat` is set to "xlf2"',
+       () => {
+         env.tsconfig({i18nInFormat: 'xlf2'});
+         env.write(`test.ts`, `
         import {Component} from '@angular/core';
         @Component({
           selector: 'test',
           template: '<div i18n>Some text</div>'
         })
         class FooCmp {}`);
-      env.driveMain();
-      const jsContents = env.getContents('test.js');
-      expect(jsContents).toContain(':@@8321000940098097247:Some text');
-    });
+         env.driveMain();
+         const jsContents = env.getContents('test.js');
+         expect(jsContents).toContain(':@@8321000940098097247:Some text');
+       });
 
-    it('should render legacy id when i18nLegacyMessageIdFormat config is set to xmb', () => {
-      env.tsconfig({i18nLegacyMessageIdFormat: 'xmb'});
-      env.write(`test.ts`, `
+    it('should render legacy id when `enableI18nLegacyMessageIdFormat` is not false and `i18nInFormat` is set to "xmb"',
+       () => {
+         env.tsconfig({i18nInFormat: 'xmb'});
+         env.write(`test.ts`, `
         import {Component} from '@angular/core';
         @Component({
           selector: 'test',
           template: '<div i18n>Some text</div>'
         })
         class FooCmp {}`);
-      env.driveMain();
-      const jsContents = env.getContents('test.js');
-      expect(jsContents).toContain(':@@8321000940098097247:Some text');
-    });
+         env.driveMain();
+         const jsContents = env.getContents('test.js');
+         expect(jsContents).toContain(':@@8321000940098097247:Some text');
+       });
 
-    it('should render custom id even if i18nLegacyMessageIdFormat config is set', () => {
-      env.tsconfig({i18nLegacyMessageIdFormat: 'xlf'});
-      env.write(`test.ts`, `
+    it('should render custom id even if `enableI18nLegacyMessageIdFormat` is not false and `i18nInFormat` is set',
+       () => {
+         env.tsconfig({i18nFormatIn: 'xlf'});
+         env.write(`test.ts`, `
         import {Component} from '@angular/core';
         @Component({
           selector: 'test',
           template: '<div i18n="@@custom">Some text</div>'
         })
         class FooCmp {}`);
+         env.driveMain();
+         const jsContents = env.getContents('test.js');
+         expect(jsContents).toContain(':@@custom:Some text');
+       });
+
+    it('should not render legacy id when `enableI18nLegacyMessageIdFormat` is set to false', () => {
+      env.tsconfig({enableI18nLegacyMessageIdFormat: false, i18nInFormat: 'xmb'});
+      env.write(`test.ts`, `
+     import {Component} from '@angular/core';
+     @Component({
+       selector: 'test',
+       template: '<div i18n>Some text</div>'
+     })
+     class FooCmp {}`);
       env.driveMain();
       const jsContents = env.getContents('test.js');
-      expect(jsContents).toContain(':@@custom:Some text');
+      // Note that the colon would only be there if there is an id attached to the string.
+      expect(jsContents).not.toContain(':Some text');
     });
 
     it('@Component\'s `interpolation` should override default interpolation config', () => {
diff --git a/packages/compiler/src/i18n/i18n_ast.ts b/packages/compiler/src/i18n/i18n_ast.ts
index 395e2e8510..807e1cac27 100644
--- a/packages/compiler/src/i18n/i18n_ast.ts
+++ b/packages/compiler/src/i18n/i18n_ast.ts
@@ -11,7 +11,7 @@ import {ParseSourceSpan} from '../parse_util';
 export class Message {
   sources: MessageSpan[];
   id: string = this.customId;
-  /** The id to use if there is no custom id and if `i18nLegacyMessageIdFormat` is true */
+  /** The id to use if there is no custom id and if `i18nLegacyMessageIdFormat` is not empty */
   legacyId?: string = '';
 
   /**