Used with 4D Server applications, client applications can be installed on an unlimited number of Mac and/or Windows machines. The number of machines allowed to connect to the server concurrently is limited by the number of Client Expansion licenses. These licenses are to be installed on the 4D Server.
Additional concurrent users can be added to your 4D Server by buying a 4D Client Expansion pack. They are available in 1, 5 and 10 unit packs.