This update for Microsoft Virtual Server R2 SP1 includes support for the following additional Host and Guest Operating Systems

Additonal Guest Operating System support:
Windows Vista® Ultimate Edition with Service Pack 1 (SP1)
Windows Vista® Business Edition with Service Pack 1 (SP1)
Windows Vista® Enterprise Edition with Service Pack 1 (SP1)
Windows Server® 2008 Core
Windows Server® 2008 Standard
Windows Server® 2008 Datacenter
Windows Server® 2008 Enterprise
Windows Server® 2008 Small Business Server
Windows XP Professional with Service Pack 3


Additional Host Operating System support:
Windows Vista® Ultimate Edition with Service Pack 1 (SP1) (non-production use only)
Windows Vista® Business Edition with Service Pack 1 (SP1) (non-production use only)
Windows Vista® Enterprise Edition with Service Pack 1 (SP1)(non-production use only)
Windows Server® 2008 Core
Windows Server® 2008 Standard
Windows Server® 2008 Datacenter
Windows Server® 2008 Enterprise
Windows Server® 2008 Small Business Server
Windows XP Professional with Service Pack 3 (non-production use only)