How ahead are you guys in the (Python) real world?

[John Salerno]

Ray wrote:

> However I wonder, how fast are you guys moving from version to version
> at work?

Interesting question. Just as a curious follow-up (not being someone who 
works in the programming world), why does it take so long to move to the 
latest version, especially when there aren't (I don't think) any changes 
that would break existing code, such as moving to Python 2.4 from 2.2 or 
2.3?

Thanks.