For those unfamiliar with the "open source version of the scalable, non-blocking web server and tools that power FriendFeed," Tornado is different from typical Python frameworks in that it is non-blocking, allowing it to process thousands of standing connections simultaneously, and making it ideal for real-time web services.  While Tornado 2.0 provided some improvements, it also created some issues with backwards compatability:

Tornado 2.0 introduces several potentially backwards-incompatible changes, including in particular automatic escaping of template output.

-- Tornadoweb.org

So it should be no surprise that the big news for this release is the improved compatability between Twisted and Tornado. Other improvements of note are:

• Updated and expanded WebSocket support
• Template errors now generate better stack traces
• Better exception handling in tornado.gen
• tornado.simple_httpclient disables SSLv2

Tornado requires Python 2.5, 2.6, 2.7, or 3.2, and is designed to run on most Unix-like platforms, though Linux and BSD (including Mac OS X) are preferred.

For a full list of features for Tornado 2.2, visit tornadoweb.org, or to download Tornado, check out the GitHub page.