Domain functional level requirements for VMM

This is a question that I see from time to time either on forums or from customers.  What is the domain functional level required for VMM?

The answer is that VMM requires the domain functional level to be at least 2003 or higher.  It is not supported to install VMM on a 2000 level domain. 

https://technet.microsoft.com/en-us/library/cc764231.aspx