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After the release of Ember 3.4 earlier this month, the Ember project released version 3.5 of the three core sub-projects: Ember.js, Ember Data, and Ember CLI. This release boasts of up to 32% performance improvement in Ember CLI build and a new Ember Data which powers the addon developers. This version also kicks off the 3.6 beta cycle for all the three sub-projects.

Additionally, Ember 3.4 is now promoted to LTS, which stands for Long Term Support. This means that Ember will continue to receive security updates for 9 release cycles and bug fixes for 6 cycles.

Let’s now explore what updates have been added in this release:

Updates in Ember.js 3.5

This version is an incremental and backwards compatible release with two small bug fixes. These bug fixes pave the way for new features in future releases.

The following bugs are fixed in this release:

  • In some cases Alias wouldn’t teardown properly leaving unbalanced watch count in meta. This is now fixed.
  • Naming routes as “array” and “object” is allowed.

Updates in Ember Data 3.5

This release hits two milestones: the very first LTS release of ember-data and the RecordData interfaces.


RecordData provides addon developers the much-needed API access with more confidence and stability. This new addition will facilitate developers to easily implement many commonly requested features such as improved dirty-tracking, fragments, and alternative Models in addons.

With this new feature added, the Ember developers are thinking of deprecating and removing the use of private but intimate InternalModel API. Also, be warned that this change might cause some regressions in your applications.

RecordData use with ModelFragments

Most of the community addons work with RecorData versions of ember-data, but currently it does not work with ember-data-model-fragments. In case you are using this addon, it is advisable to stay on ember-data 3.4 LTS until the community has released a version compatible with RecordData.

Updates in Ember CLI 3.5

Three new features have been added in this Ember CLI 3.5:

Upgraded to Broccoli v2.0.0

Earlier, tools in the Ember Ecosystem relied on a fork of Broccoli. But, from this release, Ember CLI uses Broccoli 2.0 directly.

Build speed improvements up to 32%

Now, developers will see some speed improvements in their builds, thanks to Broccoli 2!

Broccoli 2 allows Ember CLI to use the default system temp directory, instead of a ./tmp directory local to a project folder. Users may see up to 32% improvements in build time, depending on computer hardware.

Migrated to ember-qunit

As all of the main functionality lives in ember-qunit while ember-cli-qunit is just a very thin shim over ember-qunit, Ember CLI is migrated to ember-qunit. It now uses ember-qunit directly and ultimately ember-cli-qunit would become deprecated.

To read the full list of updates, check out the official announcement by the Ember community.

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