We presently sell an app and control the license with an activation code based on the serial number and a unique key on the workstation for each user.

One of our client wants to install on their Citrix server. I've been told that I should change my licensing policy (price and control) to CONCURENT instead of INSTALLED.

Since the server is at the client's location, how can I make sure (control), from my exe, the number of concurent users and make sure they have to tell us each time they want to add additionnal licenses?

TIA