By default, the PaperCut Client (v23) supports UPN-based authentication for the application itself.
However, print jobs sent to the server are still processed using the SAM Account Name rather than the UPN. This can create issues in multi-domain environments where users are synchronized using UPN format.
To work around this, you can place the PaperCut Client into KIOSK mode, which forces the client to authenticate using the UPN. Below is the approach I’ve used successfully.