We've released ZCS 4.5.5

There are about 79 fixes in this edition.
http://pm.zimbra.com/pm_patch.php?patch=4_5_5&status=Released%20(05/02/07)&rel=4.5&relName=Frank

Network Edition: http://downloads.zimbra.com/
Open Source Users: http://www.zimbra.com/community/downloads.html

john