The RDS CAL for your users or devices must be compatible with the Windows Server version to which the user or device is connecting.
RDS Daily calories for earlier versions cannot be used to access later versions of Windows Server, but later versions of RDS Daily calories can access earlier versions of Windows Server.
To connect to a Windows Server 2016 RD Session Host, for example, an RDS 2016 Someone who or higher is required, whereas an RDS 2012 CAL or higher is required to connect to a Windows Server 2012 R2 RD Session Host.
Your RDS is Something that must be installed on a compatible RD license server. Any RDS license server can host licenses from all previous versions of Remote Desktop Services as well as the current version.
A Windows Server 2016 RDS license server, for example, can host licenses from all previous RDS versions, whereas a Windows Server 2012 R2 RDS license server can only host licenses from Windows Server 2012 R2.
What port does RDS Licensing use?
What is the port number for RDS licensing? TCP Websockets 3389 Standard Remote desktop port from client to RD resource A different port number can be configured on both the host and the client.