This is just information for Citrix Administrator regarding the licenses of TS and Citrix.
In PS 3 and 4 any rdp connection will consumes a citrix license.
Example: If you have 500 TS CAL licenses but only have 30 Citrix Licenses, ONLY 30 user can connect to your Presentation Server, using Citrix client or RDP. In PS4 you can see in License Manager Console – Current Usage.
In previous versions of Citrix (MF XP) rdp connectons do not consume citrix licenses.
So, if you used an old version of citrix and want to upgrade into PS 3 or 4, consider this issues.