Ember 4.12 Released

– By Jared Galanis

Today the Ember project is releasing version 4.12 of Ember.js, EmberData, and Ember CLI.

This release kicks off the 5.0 beta cycle for all sub-projects. We encourage our community (especially addon authors) to help test these beta builds and report any bugs before they are published as a final release in six weeks' time. The ember-try addon is a great way to continuously test your projects against the latest Ember releases.

You can read more about our general release process here:


Ember.js is the core framework for building ambitious web applications.

Changes in Ember.js 4.12

Ember.js 4.12 is an incremental, backwards compatible release of Ember with bug fixes, performance improvements, and minor deprecations.

Bug Fixes

Ember.js 4.12 introduced 3 bug fixes.

  • #20388 - Don't run getters while applying mixins, ensuring that getters are never evaluated while applying mixins.
  • #20398 - Fix runloop types on TypeScript 5.0+ where types around bind were flagged with an assignability error.
  • #20385 - Improve the error for owner methods called after destroy where the error message did not indicate what was being looked up.


Ember.js 4.12 introduced 3 features.

  • #20352 - Enable generating Typescript blueprints when isTypeScriptProject is true without additional environment variables per RFC #800.
  • #20355 - Enhance the Typescript blueprint for generated services per RFC #800.
  • #20356 - Generate signature in TypeScript Glimmer Component blueprints per RFC #800.


Ember.js 4.12 introduced 0 deprecations.

Deprecations are added to Ember.js when an API will be removed at a later date. Each deprecation has an entry in the deprecation guide describing the migration path to a more stable API. Deprecated public APIs are not removed until a major release of the framework. No new deprecations are allowed after the .10 release, to minimize churn before the next major release.

Consider using the ember-cli-deprecation-workflow addon if you would like to upgrade your application without immediately addressing deprecations.

For more details on changes in Ember.js 4.12, please review the Ember.js 4.12.0 release page.


EmberData is the official data persistence library for Ember.js applications.

There were many significant changes to EmberData in 4.12, including:

  • some big steps towards Embroider support with improved build times and addons that are close to v2 addons - full embroider support is the flip of a switch away once a few issues are resolved;
  • lots of improved documentation, including the docs around Cache, Notifications, Identity Management, and Record Lifecycle, also includes inline deprecation docs and granular stripping;
  • introducing @ember-data/request and the RequestManager, a package that can be used independently (but also comes bundled with ember-data) that re-envisions how data fetching is managed for both EmberData and applications more broadly - see the docs and related RFC;
  • Cache Spec 2.1 implementation - using the power of store.request, requests are now capable of providing a cache-key or being cached by URL, with full lifecycle control and notification subscriptions. Documents are a first-class citizen of the Cache and EmberData more broadly. To go with this, the JSON:API cache previously provided by @ember-data/record-data is now upgraded to the 2.1 spec and available as the @ember-data/json-api package. While this cache does not yet implement the full suite of cache 2.1 APIs, support for all Cache 2.1 APIs has been added to the store. Read more about Cache 2.1 in the related RFC.

Changes in EmberData 4.12

Bug Fixes

EmberData 4.12 introduced 20 bug fixes.


EmberData 4.12 introduced 24 features.


EmberData 4.12 introduced 2 deprecation removals.

We are not detailing all the work done in this release, here, so for more details on changes in EmberData 4.12 please review the thorough notes on the EmberData 4.12.0 release page and the EmberData changelog

Ember CLI

Ember CLI is the command line interface for managing and packaging Ember.js applications.

Upgrading Ember CLI

You may upgrade Ember CLI using the ember-cli-update project:

npx ember-cli-update

This utility will help you to update your app or addon to the latest Ember CLI version. You will probably encounter merge conflicts, in which the default behavior is to let you resolve conflicts on your own. For more information on the ember-cli-update project, see the GitHub README.

While it is recommended to keep Ember CLI versions in sync with Ember and EmberData, this is not required. After updating ember-cli, you can keep your current version(s) of Ember or EmberData by editing package.json to revert the changes to the lines containing ember-source and ember-data.

Changes in Ember CLI 4.12

Ember CLI

Ember CLI did not introduce new bug fixes, features or deprecations, but there were a few updates that added ember-modifier and tracked-built-ins to the app blueprint and there was one update addressing a dependency vulnerability.

Bug Fixes

Ember CLI 4.12 introduced 2 bug fixes.

  • #10091 - Fix looking up the default blueprint for scoped addons
  • #10192 - The addon command should throw when no addon name is provided


Ember CLI 4.12 introduced 11 features.

  • #10122 - Add Stylelint setup to app and addon blueprints
  • #10142 - Update ESLint to v8 in app and addon blueprints
  • #10157 - Exclude ember-cli-terser when generating apps using the --embroider option
  • #10159 - Exclude ember-cli-sri when generating apps using the --embroider option
  • #10161 - Remove NPM version checking
  • #10169 - Remove app.import comment in app blueprint
  • #10172 - Lazy require heavier packages
  • #10173 - Don't delete the newly-generated app directory when an error occurs
  • #10180 - Update ember-welcome-page to v7 in app blueprint
  • #10188 - Update ESLint parser ecmaVersion to latest in app blueprint
  • #10189 - Add v4.8 LTS to addon blueprint - Remove v3.28 LTS and ember-classic scenario


Ember CLI 4.12 introduced 0 deprecations.

For more details on the changes in Ember CLI 4.12 and detailed upgrade instructions, please review the Ember CLI 4.12.0 release page.

Thank You!

As a community-driven open-source project with an ambitious scope, each of these releases serves as a reminder that the Ember project would not have been possible without your continued support. We are extremely grateful to our contributors for their efforts.