Exchange Server Supportability Matrix
says that Exchange 2016 CU3 and later support lowest forest functional level win 2008 R2 SP1.
I know that win 2008 r2 forest functional level exist but I never heard about 2008 r2 sp1 forest functional level.
I´m in proces of upgrading DCs to 2008 R2 SP1.
When I upgrade to 2008 r2 sp1 and demote old 2008 servers I presume that option 2008 r2 sp1 will be visible?