updating with yum

I'm running the latest ISPConfig 2 and I had used the Centos 5.2 guide to set it up last year. Can I safely run yum update, let it update any package it wants or are there some that need to be a certain version for 2.2.32?
Are kernel updates ok?

 

I think it *should* work, but if you want to go sure, make a backup of the system before you try it.