I would be interested in knowing this, too. AFAIK, you can't roll back. You need to backup /opt/zimbra before you upgrade it.
Originally Posted by wildhuman
This is how I backup:
rsync -avrlHKpogDt /opt/zimbra/ /opt/zimbra_synced
P.S. I would not suggest this method for incremental backup because I am not sure that if you run the same command again, the symlinks would be maintained. This needs to be confirmed. The above command lets me preserve the permissions, and I run it after switching zimbra off.
In case the upgrade is spoilt, you only need to do this:
and after checking that all is fine.
mv /opt/zimbra /opt/zimbra_temp
mv /opt/zimbra_synced /opt/zimbra
rm -rf /opt/zimbra_temp