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: