Note that I just upgraded Zope3 to use ZODB 3.4a1, same as the Zope 2.8a2 release made yesterday. I'm not sure how "Zope X3.1" relates to the Zope3 trunk, but I don't see anything that looks like "X3.1" in SVN yet, and whatever X3.1 is should also use ZODB 3.4a1.