Zimbra Collaboration Server 7.1.2 & 6.0.14: Network Edition Downloads | Open Source Edition Downloads
Please be sure to read the associated release notes for more on all the great enhancements and fixes.
- RHEL 6 (& Fedora 13) Support
- 2-way SSL auth for reverse proxy 
- Http client internal/external connection manager localconfig (see release notes for a list of new values, a few interim values are depreciated so you will have to apply changes to corresponding new attributes as they are not migrated) sInternalConnMgr & sExternalConnMgr 
- Socialcast.com integration (a newly added division of VMware!).
- Waitset fixed when mailboxes moved to another server.
- Set zimbraCalendarKeepExceptionsOnSeriesTimeChange TRUE if you would prefer to let exceptions stay untouched and don't interact with MS Exchange environments.
- If coming from a version prior to 7.1 don't forget migrate20100913-Mysql51.pl (see release notes) it's also been improved.
- Addressed Google & Yahoo Zimlet hang issues in IE.
- Servlet Spec 2.5 fix for ServletOutputStream 500 error during http head requests.
- Access & trace logs are now in /opt/zimbra/log instead of /opt/zimbra/jetty/logs for upgrades as well.
- Fixed behavior of quotes in search results.
- 6.0.14 changes include fixes for MobileWeb reply charset, declined invite issues, signatures in Chrome.
- More details on pm.zimbra.com
Other recent releases include ZD 7.1.1 build 10917 plus ZCB 7.1.2 & 6.5.7 series.
Before doing an upgrade, always remember to back up your installation. Enjoy the release!