Let's say I have a bunch of SLES 11 SP3 XEN Dom0 (hosts)
That are running a bunch of SLES 11 SP3 paravirtualized DomU (guests)

I *thought* (but can't seem to find either way) that if you want to patch to SLES 11 SP4 (for example) that you should do the Dom0 (host) first and then the guests?

Or is it the other way around?

Or doesn't it matter? (from an official support perspective that is).

I vaguely recall one time I did a DomU first (SLES 10 mind you) and it went horrible and wouldn't boot until I upgraded the host. But that was SLES 10