Citrix netscaler apx express for lab

Greetings all, can anyone direct / clarify the free license for apx express? I have a need to build apx in a lab environment however I really don’t like having to keep tabs on the lab licensing. At one point there was a free version of this software where you could have like 5 connections allowed on the apx at one time. This would be ideal for my needs but the research that I have been looking at is spotty at best on how to obtain this software.