XCP-ng is not just a "product" or a solution, it's also a great project with a great community!
A long time ago there was the free hypervisor Xen Cloud Platform - XCP and its commercial version Citrix XenServer. Later Citrix open sourced XenServer, so XCP was no longer needed and discontinued.
But since XenServer 7.3, Citrix removed a lot of features from the free version. The project founder Olivier Lambert wanted to have a free, community based, unrestriced open source hypervisor with the spirit of XCP and so he called his new project
XCP New Generation, in short XCP-ng.
The goal of XCP-ng is to make a fully community backed version of XenServer, without any feature restrictions.
Most of the community is on XCP-ng Forum. Feel free go there and ask anything!
There's also a Twitter account and an IRC channel available on Freenode: #xcp-ng
# History of XCP-ng
Here is a video recorded at FOSDEM19: