W2K8R2/W7 critical hotfix in a Citrix XenApp6/Xendesktop4 environment

I have noticed some critical issues in a W2K8R2 / XenApp6 environment.

Hotfix for W2K8R2, XenApp6

A Windows Server 2008 R2-based Remote Desktop server denies some connection requests randomly under heavy logon or logoff conditions

download here -> http://support.microsoft.com/kb/979530

Client-side rendering in Windows Server 2008 and in Windows Vista may decrease performance on Windows Server 2008-based terminal servers

download here  – >http://support.microsoft.com/?kbid=958656

Hotfix for W2K8R2, XenApp6 & Windows 7 (XD)

There is a delay when you shut down, restart, or log off a computer that is running Windows 7 or Windows Server 2008 R2 
download here ->http://support.microsoft.com/kb/975777

A computer that is running Windows Server 2008 R2 or Windows 7 stops responding randomly
download here -> http://support.microsoft.com/kb/2265716