I was assigned to upgrade a bunch of servers to the newest JBoss version. 

These servers are RHEL 4.7 , RHEL 4.8 and RHEL 5.5

I don't want to mess up so I was wondering if JBoss is still Platform-independent here or is the JAVA version gonna cause a problem?

Also can't I just "update" instead of "migrating" all the applications to the new JBoss? ( That's just something I found during some research I made)

I hope you can help me !