as there is no released version in the 2.2 and 3.0 trees version 2.1.11 appears to me the best choice for production environments.
Unfortunately, it does not run with Python 2.6 for several reasons - which brings the project in a difficult situation in medium-term. I prepared a fix for the md5/sha deprecation - but only to run into a the email.message issue (mentioned in another thread).
How much pain can I expect on the path to make it work with Python 2.6 ? I am pretty sure that Barry or Mark already investigated to some extend. Please share insight :)