R2 and Domain Function Levels
We have an odd setup where we are, with a Forest and 2 sub domains, we are currently running at 2003 level, everything works.
Now from my understanding, some features of 2008R2 like direct access and branch cache need us to be running at 2008R2 functionality level. Upgrading the forest and one of the two domains is possible, however the second domain we dont control, they just connect to this one for access and facilities.
I have read conflicting answers to this, but if we were to upgrade the forest to 2008R2 level, would this prevent access from any domain that is connected running in an older functionality mode?