Ember 1.0 Prerelease 2 is out now. This is mainly a bug fix release
after 1.0.pre. However, there are a few things you should be aware of
and we'll go over those a bit below. We're still pushing hard toward the a 1.0 beta release but wanted to make some of our bug fixes available in a more formal way. If you want to go ahead and
download now, you can grab it over on the Github Download Page.

What's Changed Now
Other than bug fixes, there are a few things we've changed that
could affect your 1.0.pre apps.

• {{outlet}} now creates a Metamorph rather than a . This makes
  it less obtrusive, but you may have to change your HTML or CSS if you
  were relying on the .
• We have removed CP_DEFAULT_CACHEABLE and VIEW_PRESERVES_CONTEXT
  flags. Both behaviors are now always on.
• Inline Handlebars templates must always be named now. The default name
  is 'application'. This means that
  behaves exactly the same as
  .
• Using the {{collection}} helper without a class has been deprecated,
  use the {{each}} helper instead. The {{each}} helper also now
  supports itemViewClass which was the main benefit to using
  {{collection}}.
• Ember.ViewState has been removed.

For more information on what's been changing in Ember, take a look at
Bradley Priest's What's New in EmberJS.
What Will Change Later
There are still some things that we want to take care of before we do a
beta release. Here are a few of them:

• New Router API: This is mostly finalized but has not yet been
  implemented.
• New Computed Property API: We're working on a new API for Computed
  Property getters and setters. Don't worry, we expect to support
  the existing one for the foreseeable future.
• Asynchronous Observers: Currently observers are fired immediately
  whereas bindings are synchronized with the RunLoop. In most cases
  observers can and should be delayed for optimal performance. We plan
  to change the existing behavior and add a new API for the cases where
  immediate execution really is needed.