Can re-use Server 2019 keys on same server to upgrade server 2016 downgraded from same/original 2019 license?

Question

In 2019, we bought a new server, bout 2 x Server 2019 licenses - however those were downgraded to 2016 because of other software which didn't run on 2019, at that time.

Today, we need to install software which runs on 2019, not 2016 and not 2022. (All our software today runs 2019 server).

Can we use the same the same keys/license for the original 2019 server license purchased in 2019 to upgrade our original 2016 downgrade from 2019?

Basically, we already bought 2019, but downgraded it.
Now we want to upgrade to 2019 and use our originally used keys to install 2016 server?

Sorry, I'm a mere user..... our IT support is telling us we have to purchase 2022 and downgrade to 2019 which seems bonkers when we already purchased 2 x 2019 licenses (although downgraded at that time). we just want to use our original licenses for what they were bought for and not buy more to downgrade!! Upgrade 2016 to 2019 using our original purchase keys.

I do hope that is clear for someone.
Thank you very much.

Answer 1

If you are using the same server you bought the licenses for, then yes, you can just use the licenses you purchased initially. If they were OEM licenses, they live and die with the hardware. If they were purchased 'retail' then they can move between hardware but not often and obviously must not be used on the one it came from. If they were purchased as a volume license, they can also move between hardware, at a minimum of every 180 days if I recall correctly.

If you are in-place upgrading your server (https://www.ajtek.ca/wsus/another-successful-in-place-upgrade-why-not-change-how-you-think/) then just upgrade and use the original keys for 2019.
If you are backing up (or not) and wiping and installing server 2019 on that hardware it was purchased for, then use the original keys.