CARP between 4.7 and 48 possible?

[Marcus Mülbüsch, AS-Infodienste GmbH (Systemadministration)]

A quick question: Is it possible to make a carp interface between two 
machines if one is running on openBSD 4.7 and the other on openBSD 4.8?

Background: Finally a got a second machine for our Firewall. Since the 
working one runs on 4.7 and I am reluctant to upgrade it before I got 
the second one working I try to CARP the interfaces first, then get the 
new one working, then take the first one of the net and upgrade it to.

So far both machines claim to be master on an active/active 
configuration on both assigned VHIDs. It's entirely possible that I 
misconfigured something, but before I check everything a third (fourth, 
nth) time I'd rather be sure that that has nothing to do with the 
machines being on a different version.

Marcus