How to determine what type of SQL Server license is currently being used?

I believe this is an administrative thing; SQL Server does not track this information by itself.  Look at what you purchased when you purchased it.

And since licensing does change, I might suggest it doesn't matter what you DID pay for it.  Look at what you need now; you'll need all new CALs anyway.

Hi Lee,

Thank you for responding. I was unsure how to classify the question. Should i reclassify and resubmit? There are completely different employees here from when the SQL server was installed previously so tracking down the PO is proving to be a challenge.

Again, it doesn't really matter.  You're upgrading.  There is no special pricing for upgrades.  If you had software assurance, you'd have to have renewed it at most 2 years ago.  But you need all new licenses.  Look at the environment now, look at the licensing options NOW, and purchased based on today. What you had yesterday really doesn't matter.

SELECT @@VERSION

Microsoft SQL Server 2019 (RTM-CU10) (KB5001090) - 15.0.4123.1 (X64)   Mar 22 2021 18:10:24   Copyright (C) 2019 Microsoft Corporation  Developer Edition (64-bit) on Windows 10 Home 10.0 <X64> (Build 19042: ) (Hypervisor)

 Thank you, experts!