CVSUP upgrade 5.0 -> 5.1

[Guy Van Sanden]

I've been contemplating upgrading my FreeBSD 5.0 to 5.1 using cvsup
(mainly since there is no official security branch for 5.0 anymore)

What I wanted to ask is if I might expect some ports to break after it.
I'm running Bugzilla (on MySQL), apache, Big Brother (not from ports),
NTP, Samba, tinydns, dnscache and some others.

I want to be prepared to handle these befor attempting the upgrade.

Thanks 

Guy