The dependencies of ember-intl (in particular, @types/ember__runloop and @types/ember__template) have been updated to the latest version. This may fix the error messages shown below:

[lint:types] node_modules/ember-intl/-private/formatters/-base.d.ts:1:33 - error TS2307: Cannot find module '@ember/template/-private/handlebars' or its corresponding type declarations.
[lint:types] 
[lint:types] 1 import type { SafeString } from '@ember/template/-private/handlebars';
[lint:types]                                   ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
[lint:types] 
[lint:types] node_modules/ember-intl/-private/formatters/format-message.d.ts:1:33 - error TS2307: Cannot find module '@ember/template/-private/handlebars' or its corresponding type declarations.
[lint:types] 
[lint:types] 1 import type { SafeString } from '@ember/template/-private/handlebars';
[lint:types]                                   ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
[lint:types] 
[lint:types] node_modules/ember-intl/services/intl.d.ts:1:36 - error TS2307: Cannot find module '@ember/runloop/types' or its corresponding type declarations.
[lint:types] 
[lint:types] 1 import type { EmberRunTimer } from '@ember/runloop/types';
[lint:types]                                      ~~~~~~~~~~~~~~~~~~~~~~
[lint:types] 
[lint:types] node_modules/ember-intl/services/intl.d.ts:3:33 - error TS2307: Cannot find module '@ember/template/-private/handlebars' or its corresponding type declarations.
[lint:types] 
[lint:types] 3 import type { SafeString } from '@ember/template/-private/handlebars';
[lint:types]                                   ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Thanks to @jelhan.