In case you missed them this month, Citrix published 2 KB articles detailing the End Of Life support plans for their current XenDesktop products.
XenDesktop 3 is end of life at the end of this year, and there won’t be patches after 10/28/10. XenDesktop 4 however, will be supported through 5/2014.
XenDesktop 3 - http://support.citrix.com/article/CTX124351
XenDesktop 4 - http://support.citrix.com/article/CTX124352
It’s interesting to me that XD3 which was released in February 2009 will have it’s support pulled so soon while XD4 is slated to have support until 2014. From my perspective, it seems that most of the XD3 implementations where still in Test/Dev while XD4 has made inroads into production environments making support of the product more critical and requiring the customers to upgrade more of an issue. I would imagine that from now to 2014, at least 2 more major revisions will be released to the public. XenDesktop 6 anyone?