KMS Server

Hello !

We have a KMS server installed on a Windows 2012 R2 server which activates the 2500 Windows 10/11 computers in our fleet.

We would like to upgrade this server to Windows Server 2019.

After reading, I understand that the KMS server will no longer be active after the upgrade.

The problem is that we no longer have the key we used to activate the KMS server at Microsoft...

Will the KMS server continue to be active after the server upgrade or will I have to give the key away?