Today, we're releasing the second Release Candidate of Ember 1.0.
As we said when we released RC1, the next few releases will be
about bugfixes and improvements, and should not have any breaking
changes.
Namespace Lookup for Controllers
It is now possible to look up controllers that are included in a
namespace other than the main application namespace.
For example, when using the render helper:
{{render 'posts'}}

This will render the posts template with the controller App.PostsController, where App is the main application namespace.
If you want to use an alternative namespace, you can use a
/-separated path.
{{render 'blog/posts'}}

This will render the blog/posts template with the controller
Blog.PostsController.
Using Render With Multiple Models
In RC1, you could use {{render 'posts'}} to render the posts
template using the app's instance of App.PostsController. Using
render in this way will always render the template using the same
singleton controller.
In RC2, we are adding the ability to render a template with a
particular model: {{render 'post' post}}. When you supply a model,
Ember.js will create a new instance of the App.PostController each
time it is used.
This allows you to use {{render}} in a loop:
{{#each post in posts}}
{{render 'post' post}}
{{/each}}

Unwrapping an ObjectController's Model
When passing an ObjectController as a parameter to the action
or linkTo helpers, Ember now unwraps the underlying model and
passes it through.
Most importantly, this allows you to add an itemController to
{{#each}} without affecting action handlers in your controller
or router.
If you have a template like this:
{{!-- posts.hbs --}}

{{#each controller itemController='postItem'}}
• {{name}}

{{/each}}

Your App.PostsController would look like this:
App.PostsController = Ember.ArrayController.extend({
needs: 'currentPost',

selectPost: function(post) {
// `post` here is an `App.Post`, not an
// `App.PostItemController`
this.set('controllers.currentPost.model', post);
}
});

This should make using itemController less gotcha-prone.
Support for jQuery 2.0
Ember 1.0 RC2 supports jQuery 2.0.
This allows you to use a smaller, optimized build for newer browsers
that is fully compatible with Ember.
If you're targeting both older IE and modern browsers, you can use
the following snippet to get the best of both worlds:

Because jQuery 1.9 and 2.0 are API-compatible, this strategy will
allow you to target the widest range of browsers, but ship a
smaller build for modern browsers.
The future is here!
Changelog
The full CHANGELOG is available on Github, as always.