UserPrincipalName/Primary SMTP Caveats

[Olliedawg]

Our users have the following formats set for their UPN & Primary SMTP (on prem hybrid to exchange online)

 

UPN: [email protected]

PrimarySMTP: [email protected]

 

So both of these are different, which I believe is against the best practice?

 

For some applications we see that Microsoft SSO can easily break where the application only has the PrimarySMTP address, and the users Microsoft account is logged in with the UPN.

 

For example, Senso V2 we imported some users using their PrimarySMTP address, and SSO doesn't work. If we use their UPN, it does work.

 

Are there any major caveats to making these both the same? Maybe making the old UPN an alias? I understand that the UPN is used to actually log in to Microsoft 365, so that would need to be communicated to users. 

 

Suppose I can also just import the UPN address instead which would enable SSO to function.

Edited May 22 by Olliedawg

[Noxid_w]

So you want the primary SMTP the UPN? Should be fine to change UPN, it's no different from doing a name change if someone gets married. Make sure the format in proxyaddresses is:

SMTP:[email protected]

smtp:[email protected]

 

It's case sensitive. Obviously test and confirm.

[Olliedawg]

Basically yes.

 

Makes sense, so then you have the previous UPN as an alias address. I'll do some testing.