carp no working after upgrade

[Gábri Máté]

Dear List,
i have a FreeBSD 7-release cluster firewall using carp for the public IP
addresses. Last evening i've upgraded one of the firewalls to 7-release-p5
and after that carp stopped working. The two nodes can't understang each
others cap packets so both of them are in master state. Does p5 differs from
the original release so that the carp packets are different two?