Yesterday marks the latest and probably final Ext release before 2.1. Latest releases are always available via http://extjs.com/download
As usual there are quite a few bug fixes, and some nice refactorization. This release also includes a whole bunch of new code to aid with developing an Adobe AIR app with Ext. Jack has spent a great deal of time over the past few months to build some nice wrappers and make using Ext with Air amazingly simple. Jack wrote a lengthly blog post that goes into detail about all the cool new Air components over on the official Ext blog.
Aside from just Air stuff, Jack managed to sneak in a couple cool components that very well make work their way into the core release. The ListTree is a combination of a Combobox and a TreePanel and definitely looks to be a slick way to select from hierarchical data. Check out the post for more info and links to grab the latest version of the Air app to play with.