Adobe DC licensing in an RDSH/Citrix environment

Client wants to run Adobe DC in their Remote Desktop Session Host/Citrix XenApp environment. Looking for a definitive answer if they need licences for all Users on all Servers, or just the Users of the Adobe DC product?

We could control access with Windows GPO if that meets with Adobe licensing constraints, but we have nothing official like AppSense EM or FSLogix to physically prevent access, so wanted to know the requirements.

Thanks in advance