> There are some issues when updating from Zope 2.5.1 to 2.6.x. I wrote a > how-to > some months ago with the problems I had: Ops, sorry, I realized that you want to do the oposite. Anyway, I think that the chances you have problems are bigger because there are some new features that 2.6.1 has and 2.5.1 doesn't.