Naturally, one should start by reading the very informative Zimbra 8.0.0 GA Release Release Notes. I am glad to see the "Inline reply", "Autocomplete matches now work correctly for Contact Groups" bugs fixed! The "Per folder message retention policy creation" added is long overdue IMHO. Don't short change your upgrade by skipping the release notes. You *should* take the time to go through it!
As root:
screen
tar -xzvf zcs-8.0.0_GA_5434.RHEL6_64.20120907144639.tgz
cd zcs-8.0.0_GA_5434.RHEL6_64.20120907144639
./install.sh --platform-override
To get the new 5 year default SSL cert, you will want to run as user zimbra:
sudo /opt/zimbra/bin/zmcertmgr createca -new
sudo /opt/zimbra/bin/zmcertmgr deployca
sudo /opt/zimbra/bin/zmcertmgr deploycrt self
Production server upgrade note (10/29/2012):
The Zimbra 8.0.0 upgrade/install seems to have reset several of my custom settings to default attributes! I have made most of my custom changes based on the very handy Zimbra wiki for Performance Tuning Guidelines for Large Deployments in the past. The main changed items I've spotted so far are zimbraImapMaxConnections and zimbraImapNumThreads that reverted back to 200. I hope not to find too many more production system oddities! The reason I noticed the issue is that the /opt/zimbra/log/mailbox.log had MANY messages like:
WARN [ImapServer-76] [] imap - Dropping connection (max connections exceeded)
WARN [ImapServer-80] [] imap - Dropping connection (max connections exceeded)