It is a major release packed with lots of new features but incompatible with previous versions.
Most of the asynchronous internals have changed to make way for the new asyncio module in the python standard library.
The new release supports python 2.7, 3.3, 3.4 and pypy.
Major changes:
* Python asyncio module has replaced most of the low level asynchronous internals
* Dropped support for python 2.6 & 3.2
* Coroutines work with *yield* as well as *yield from*
* New datastore application supporting redis & pulsar-datastore
* Better websocket support
Full release notes
Luca