Citrix XenServer MxGPU support is currently offered only as a technical preview. This Citrix solution has been tested with Citrix XenDesktop 7.15 and Citrix XenServer 7.2. Citrix XenDesktop and XenApp on ESX 6.x here: http://support.amd.com/en-us/download/workstation?os=VMware%20vSphere%20ESXi%206.5#release-notes