Could I run #zmprov gaa -v on my 4.5.11 zimbra server then use that output with #zmprov ca on my 5.0.6 zimbra server to import the accounts and their settings?

I then would use imapsync to copy all the emails, docs, calenders from 4.5.11 to the new server 5.0.6.

Comments please.

FYI, I have this nagging problem that when I upgrade from 4.5.11 to any of the 5.0.x releases there is an error with the postfix I can't fix.
So I need more space on my server anyway so I may as well upgrade to to a newer OS and a larger hard drive.