Posted 16 February 2017 - 05:24 PM
Citrix License server is a component of Citrix XenDesktop / XenApp product suite. Considering Citrix recommendations you should always upgrade use the latest License server component as its a requirement for new product version to enable all features.
There is nothing like 7.6 or 7.12 license server, License server has its own version and can be downloaded from Citrix website. the latest version is 18.104.22.168 Build 18001
with the latest versions of license server you can use the new and legacy license file. License server is backward compatible to work with legacy products. so ideally upgrade your license server to the latest version and stick your 7.12,7.6 licenses into myfiles directory and restart the licensing service. if you've built a new license server, make sure you update this in studio with the new license server name under licensing.