I opened a ticket a few days ago with support for our new Network Edition installation but they haven't replied. I'll post the question here:
I have Zimbra Open Source Edition on Ubuntu 8.04 (5.0.11_GA_2695.UBUNTU8_64 UBUNTU8_64 FOSS) on two servers. I have since purchased licenses for Zimbra Network Edition. We have millions of messages in gigabytes of mailboxes so an rsync snapshot, export, and re-import would cause probably a whole day of downtime. What's the best way to upgrade an in-place installation of Open Source Edition to Network Edition without all that downtime?