Thank you, I had not found the most recent version of that document. So
the answer is "yes":
"Downgrade rights in the Volume Licensing programs provide customers
with the right to downgrade to any prior version of the same product."

Milly Staples [MVP - Outlook] wrote:

Please read the section on "Downgrade Rights Chart" for more
information for your scenario.


http://www.microsoft.com/licensing/a...ng-briefs.aspx