Ember 2.12-LTS, Ember 2.13 and 2.14 Beta Released

– By The Ember Team

Updated on December 19, 2017 to include information about Ember.js 2.12-LTS.

Today the Ember project is releasing Ember.js 2.12 LTS (a long-term support release) and version 2.13.0 of Ember.js, Ember Data, and Ember CLI.

This release also kicks off the 2.14 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.

Ember.js 2.12-LTS

Ember 2.12-LTS is our third long-term support release. You can install it by upgrading ember-source to ~2.12.2 in your package.json.

The LTS channel is designed for Ember users who would like to upgrade less frequently, while still getting support from the project and the wider ecosystem. At the same time, it allows addon authors to know which versions of Ember to focus their effort on.

Per our usual policy, Ember 2.12-LTS is released six weeks after the 2.12.0 stable release. This allows ample time to fix any reported regressions and ensures a rock solid LTS release. It will continue to receive critical bugfixes for six release cycles (roughly Janurary 2018), and security patches for ten release cycles (roughly June 2018).

Meanwhile, Ember 2.8-LTS will continue to receive critical bugfixes for another two release cycles (roughly July 2017), and security patches for six release cycles (roughly February 2018). Users of Ember 2.8-LTS should make use of this overlapping period to transition over to Ember 2.12-LTS.

For more details on the changes landing in Ember.js 2.12-LTS, please review the Ember.js 2.12.2 CHANGELOG.

Changes in Ember.js 2.13

Building on the addition of factoryFor in Ember 2.12, Ember 2.13 changes the way dependency injection is implemented in the framework. Until 2.12, dependencies were injected onto an instance using extend to create a subclass. This created an excessive number of subclasses during the execution of an application. In Ember 2.13 injections are passed to an object via create during instantiation. This results in a notable performance improvement that grows in impact with the complexity of an application.

See RFC #150 and pull request #14360 for more details about this change.

Additionally, this release contains a further refinement on the "binary VM" change landed in 2.12. By using integers for common Glimmer wire-format strings, compiled template sizes in 2.13 will see an incremental size reduction.

In addition to these and other improvements, several changes arising from the RFC process have been implemented:

  • RFC issue #146 advocated for the addition of resumeTest as a compliment to pauseTest. This was implemented in #13663.
  • RFC #186 describes the addition of uuid as a property on HistoryLocation adapters for the router. This addition makes it possible to track scroll locations to a point in browsing history. See pull request #14011 for more details.

Deprecations in Ember 2.13

A bit of cleanup has been done to reduce confusion (during implementation of the router service) which resulted in adding a deprecation for accessing the private router property of the router. This property has always been private API, but a number of addons have resorted to using it due to lack of public API options (though the router service should address these remaining cases). Please review the deprecation guide for more details.

For more details on the changes in Ember.js 2.13, please review the Ember.js 2.13.0 release page.

Upcoming Changes in Ember.js 2.14

Ember 2.14 is shaping up to be largely a bugfix release, containing a significant amount of internal cleanup.

For more details on the upcoming changes in Ember.js 2.14, please review the Ember.js 2.14.0-beta.1 release page.

Ember Data

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

Changes in Ember Data 2.13

Ember Data 2.13 represents the work of 20 direct contributors and over 120 commits.

The ds-extended-errors (#3586 #4287) feature has been enabled for Ember Data 2.13.

This feature introduces an extend method on errors which allows users to create their own custom errors that extend from DS.AdapterError.

const MyCustomError = DS.AdapterError.extend({ message: "My custom error." });

The feature also introduces some new errors to the REST adapter which will be used to reject the adapter promises based on http status of the API response.

  • [401] DS.UnauthorizedError
  • [403] DS.ForbiddenError
  • [404] DS.NotFoundError
  • [409] DS.ConflictError
  • [500] DS.ServerError

Thanks to tchak and twokul for their work on this feature and lindyhopchris for his help documenting the feature.

Deprecations in Ember Data 2.13

Ember Data 2.13 deprecates the data-adapter, injectStore, transforms, and store Ember application initializers that Ember Data injects into apps. The deprecation was proposed via an RFC, and the Ember Data team proactively submitted pull-requests for all usages of these initializers in open source addons.

For more details on the changes in Ember Data 2.13, please review the Ember Data 2.13.0 release page.

Upcoming changes in Ember Data 2.14

In 2.14, Ember Data continues its internal refactorings and performance work without impacting public APIs. It is shaping up nicely with reduced asset size (~ 3KB savings), better warnings and errors around malformed JSONAPI payloads, and simplified internals.

Deprecations in Ember Data 2.14

Ember Data 2.14 deprecates the private method didUpdateAll. If you are using it in your codebase please use the updated methods name _didUpdateAll.

For more details on the upcoming changes in Ember Data 2.14, please review the Ember Data 2.14.0-beta.1 release page.

Ember CLI

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

Upgrading Ember CLI

You may upgrade Ember CLI separately from Ember.js and Ember Data! To upgrade your projects using yarn run:

yarn upgrade ember-cli

To upgrade your projects using npm run:

npm install --save-dev ember-cli

After running the upgrade command run ember init inside of the project directory to apply the blueprint changes. You can preview those changes for applications and addons.

Changes in Ember CLI 2.13

Add support for using yarn

Ember CLI projects have been able to utilize yarn for dependency management for quite some time, however it was not well supported by the default generators. In 2.13, Ember CLI is now "yarn aware", and will use yarn for tasks such as ember install if it detects that yarn is installed and a yarn.lock exists in the project. You can even instruct ember new to generate a new project with a yarn.lock for you via ember new foo --yarn.

Enable Instrumentation Hooks

Ember CLI has had the ability to generate custom instrumentation output for builds for a few years now (introduced on 2015-08-24), but this information has not been readily accessible. In 2.13, ember-cli exposes this information to addons that implement the instrumentation hook. This allows addons to access many things that were previously very difficult (e.g. reliable build time reporting).

Thanks to @hjdivad for proposing and implementing this feature. Please read through the RFC for more details.


In order to allow addons to understand the desired target platforms of the app that they are operating in, a new file has been added to all generated projects: config/targets.js. This file exposes the supported targets so that tooling such as autoprefixer and babel-preset-env can properly understand the level of transpilation that is needed.

Thanks to @cibernox for proposing and implementing this feature. @rwjblue recently wrote a blog post reviewing the new feature and how to utilize it: Ember CLI Targets.

Babel 6

Babel 6 support has been added to Ember CLI internally and is now used by default for newly generated projects (both applications and addons). Due to the way that Ember CLI handles transpilation this transition can be done gradually by updating each addon to utilize newer versions of ember-cli-babel. Here's how to update your application to start using Babel 6 for its own transpilation:

# if using yarn:
yarn upgrade ember-cli-babel@6

# if using npm:
npm install --save-dev ember-cli-babel@6

Other Notable Changes

  • bower.json is no longer included in a newly generated project.
  • Fix command interruption issues on windows.
  • Added filesToRemove property for custom blueprints.

For more details on the changes in Ember CLI 2.13 and detailed upgrade instructions, please review the Ember CLI 2.13.0 release page.

Upcoming Changes in Ember CLI 2.14

In Ember CLI 2.14, support was added to ember new to allow a blueprint to be consumed from an NPM package. This enables projects to utilize Ember CLI's ergonomics to generate non-Ember applications. Common examples of this are:

To do so, run in your terminal:

npm install -g ember-cli@2.14.0-beta.1
ember new ember-cli-deploy-hello -b @ember-cli-deploy/plugin-blueprint

For more details on the changes in Ember CLI 2.14.0-beta.1 and detailed upgrade instructions, please review the Ember CLI 2.14.0-beta.1 release page.

Thank You!

As a community-driven open-source project with an ambitious scope, each of these releases serve 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.