UPN Suffix Case Sensitivity

Question

Is a UPN suffix case sensitive? Is it possible to have identically named UPN suffixes distinguished only by case?

Answer 1

Because of Active Directory's heavy integration and reliance upon DNS, it'd be impossible for UPNs to be case sensitive. In DNS case is ignored, so in Active Directory case is ignored.

You can add another UPN with a different case, but you can't create 2 users with the same username but a different case sensitivity in the UPN. It'd just be a cosmetic thing.