My Zimbra server is running under virtual called xen server. it is under centos 5. I use 2 server , 1 as main server the other is for backup incase the 1st one hang or freeze.

so is it possible to upgrade directly from my main version the the newest, is there any step by step instruction i can use to?

please help.

i kinda newbie here. because on the 1st installation in our zimbra server using 3rd party company, but i want to upgrade by myself.

thank you