Ember 2.0 is not a traditional major release. After thirteen point releases in
almost two years, we're taking a turn to focus entirely on sweeping out
built-up cruft as a foundation for continued progress.
Ember 2.0 only removes features that were deprecated as of Ember 1.13, so
apps that run on Ember 1.13 without any deprecation warnings should run
without issues on Ember 2.0.
New applications should begin using Ember 2.0 today. Apps requiring Ember-Data
should use Ember-Data 2.0.0-beta.1 (2.0 release coming shortly!).

For the past several years, when we've talked about "Ember releases", we were always talking about releases of the Ember codebase itself.
In practice, that has meant that in order to put together the full, recommended Ember stack, you needed to figure out not only what Ember version to use, but also what versions of our other libraries and tools worked with it.
Starting with Ember 2.0, we will coordinate every release of Ember with releases of the main ecosystem tools maintained by the core team:

Ember Data 19.1 contains fixes for a few regressions. Thanks to everyone
who reported issues. Thanks to @bmac and @wecc for fixing!

• Fix a regression where a DS.Model's InternalModel would not be set
  on init - @bmac Pull Request
• Pass store to inverseFor in removeEmbeddedForeignKey #3270 - @wecc
  Pull Request

We're a few weeks away from the release of Ember 1.13 and Ember 2.0 beta, and while there's been a lot of focus on those releases, the trains will keep rolling on June 12. There will be a 2.1 release 6 weeks hence, and a 2.2 release 6 weeks later.

With all of the focus on Ember 2.0, it's easy to forget that 2.0 is just a six-week release, with the added ability to remove some built-up cruft. Because of the symbolic nature of 2.0, discussions about the future have had an artificial end date of June 12, which is now three weeks away.