[Zope-dev] Re: [Zope2.8.7] with Five 1.0 or Five 1.2

Chris McDonough wrote:

-1... Five 1.2 has quite a few differences from Five 1.0 that would stop products written for Five 1.0 from working properly. I've not gone to 2.9 on a few projects for this reason (sticking with 2.8). 2.9 is where the new version belongs, IMO.

Out of curiosity, what are the incompatibilities between Five 1.0 and 1.2/1.3 that hinder you from upgrading?