We have a hybrid deployment and have run into some troubles managing mail settings from the on-prem DCs. I believe the solution is to raise the functional level of the forrest to 2016, but I want to confirm before migrating.
Domain controllers run on Windows Server 2012 R2 Datacentre and current functional level matches. We use a mail-enabled security group for all staff. (staff@domain.tld) We need to restrict which internal users can send mail to all staff. Exchange admin keeps telling us to make the change on-prem. Our DCs seem to have no idea that this type of group is possible, and we cant find any way to manage the group on-prem.
Am I correct in thinking we need to raise the functional level to 2016? Is there an update we can apply to get this functionality from a forrest at 2012 level, or are we out of luck?
Tried to manage a group in the usual way (AD Users and Computers), on-prem AD thinks it's a security group and NOT a distribution group - Azure AD knows it's a mail-enabled security group.