Zimbra Upgrade 7.x to 8.x
download 10.04 8.x archive from
http://www.zimbra.com/downloads/os-downloads.html
extract
run install.sh
verify Zimbra is working
run do-dist-upgrade
restart (zimbra will not start)
download 12.04 8.x archive from
http://www.zimbra.com/downloads/os-downloads.html
extract
run install.sh (do not do db verify it will fail)