I know I have had this conversation with many of you regarding the requirement to have the highest Windows Server in the environment set the CAL version, and my previous blog posts on Windows Server Licensing and CALs have always stipulated this requirement, we have listened to feedback and made some very good licensing changes as below:
Currently, if your physical server environment is running Windows Server 2003, matching version CALs are required for all users (i.e. Windows Server 2003 CALs).
However, if you move your physical Windows Server 2003 Operating System Environments (OSE) to run as virtual machines hosted by Windows Server 2008 Hyper-V, Windows Server 2008 CALs are required. This is per the current product use rights HERE
With the change in our licensing policy, Windows Server 2008 CALs are no longer required if you are using Windows Server 2008 solely as a Virtualisation host. The only exception to this is if you are running Windows Server 2008 virtual machines, which would require Windows Server 2008 CALs.
To help demonstrate the effect of the licensing change, I have included three scenarios below and the resulting requirements.
Note: This change will be in effect for all Windows 2008 Server Licenses both with and without SA coverage and any prior Windows Server Licenses that are covered with active SA or EA
More info in the new updated licensing briefs HERE