How is the Zimbra Collaboration Suite licensed with VMware?
The Zimbra Collaboration Suite (ZCS) Open Source Edition is available in both source code and binary or executable formats. Zimbra Collaboration Suite Open Source Edition binary releases are licensed under the terms of the Zimbra Public End-user License Agreement (EULA). Zimbra Collaboration Suite source code is licensed under the terms of the Zimbra Public License (ZPL).
ZCS Network Edition is Zimbra's commercial software and service subscription; it is available under the Zimbra Network Edition Evaluation License.
What is the YPL?
From Oct 3, 2007 to February 1 2010, all Open Source Edition source code releases of ZCS were made available under the Yahoo! Public License (YPL). Only older version of ZCS during Yahoo!’s ownership used this license and it is no longer current as of the VMware acquisition of Zimbra; all source code starting with ZCS 6.0.5 is governed by the Zimbra Public License (ZPL).
Are you changing the ZCS to a closed-source product at VMware?
No. We are continuing to offer the Zimbra Open Source Edition, both in source code and binary formats, for use and redistribution as you see fit, all free of charge.
Can I continue to use ZCS Open Source Edition binaries I already have?
Yes, of course! The terms under which you received your binary copy of ZCS were perpetual and remain in effect.
Suppose I still want to get the older versions of the ZCS Open Source Edition binaries. Where did they go?
They are alive and well here: http://www.zimbra.com/downloads/os-downloads-previous.html