[Zope] upgrades and stability

[Dennis Allison]

We've been using Zope 2.51 on RH 7.3.  It's been exceptionally stable
and easily handles our workload.

We are now about to refactor the system, add new features, add multiple
hardware servers, some with ZEO front-ends, go to an multiple instance
organization, to scale up for another order of magnitude or two of users.
We are having to rethink system security (e.g., SSL), backup strategies,
and add fail-soft support.

If we are going to migrate to another Zope release, now would be a good
time.  What advice would you give.  Zope 2.6.1 would be the obvious choice
although if Zope 2.7.X will be released soon it might be another
possibility.

Any advice?  hidden gotchas?  release schedule intelligence?

Thanks.