We'd be happy with 4.5 RC1 or 4.5 beta1. We configured Zimbra 4.0.4 Network Edition on a CentOS 4.4 VMware VM ourselves about 10 days ago for evaluation. We'd like to know if it can be upgraded to 4.5 Network Edition.

If we switch to the 4.5 beta1 Network Edition VMware appliance, would we lose some of our configuration settings, and possibly lose some flexibility?

One reason we'd like to upgrade asap for our evaluation is we've heard 4.5 may have document versioning / version control (is this correct?). That's a critical feature for us, and many of our clients.

Any thoughts will be appreciated.