So one our sister companies asked us to correct their UPN in the local Active Directory, so they could login in to Teams with the correct UPN.
This is totally new for me, so what could I expect?
What are the risks when changing a UPN?
They only use Teams in Office 365, no other services.
They are using a local Exchange server for mail.
They do not know if they log anywhere else in with the UPN.
Please help me to identify the risks, the do's & don'ts for changing the UPN.