[f1vefour]

Should be able to simply do this to revert to a older version:

sudo apt-get install xbian-package-xbmc=2.1

Personally I stick with 2.0, without a doubt the most stable revision on my Pi and the only version that sends the media info of streaming files to Yatse (XBMC issue not Xbian as it's the same on OpenELEC).