I guess it could be done easily via Powershell and the AzureAD module however I've got couple of doubts and it seems I can't find the proper documentation to help me to dispel them.
- When I change the UPN in AzureAD will it be automatically changed and propagated to Microsoft 365 services especially Exchange Online? Or should I then change UPN in EXO too?
- When I change the UPN in AzureAD the PrimaryEmailAddress should change too, is there an automation to keep the former address as alias (I mean, SMTP and smtp entries in the proxyaddress field)
Thanks in advance for your help.