XenApp 6.5 and XenDesktop 5.5 released
Citrix have released new versions of both XenApp and XenDesktop.
Issues fixed in XenApp 6.5: CTX130371 - Issues Fixed in Citrix XenApp 6.5 for Windows Server 2008 R2 - Citrix Knowledge Center
Issues fixed in XenDesktop 5.5: CTX130369 - Citrix XenDesktop 5.5 - Issues Fixed in This Release - Citrix Knowledge Center
However, it doesn't appear that you can upgrade from a previous version - you need to do a clean install followed by a migration:
Installing and Configuring XenApp - Citrix eDocs