I tried using my old Gateway 9.X license for my new install of gateway 10, but it would not accept my gateway 9.x license.
Do we need a new license for Gateway 10?
Release : 10.X
Component : API GATEWAY
Your gateway 9.x license will not work on gateway 10.x
You will need to request a new Gateway 10.x license for your new (or upgraded) gateway from our licensing team.
Here is a doc on how to request a new license if you are unaware of how to do so: How to request a new License
If you need to know how to install your new Gateway 10.x license or remove your old Gateway 9.x license please see our doc on managing gateway licenses.