I'm planning to change the User Principal Name attribute from mail to userPrincipalName.
(The top right sync option in the image below.)
I'm wondering whether this has any effect for my existing users?
Will the UserPrincipalName attribute in Azure AD for existing users be stay unchanged, or will it be updated with the on-premises UserPrincipalName?
In either case, I do not expect any disruption at user sign-on, as we use ADFS, so the sign-on attribute is independently defined in in the claim rules. Am I correct with this conclusion?