Hi Jan,
There’s actually no community SYS, as such, just a community APP.
I just used Marco’s SYS as a starting point.
We’ll probably move to the “official” SYS some time soonish, as Marco doesn’t have time to keep developing this.
Wildcat made an APP version with lot’s of changes, one of which is the usage of the “official” SYS, but unfortunately he made all the changes over a pretty old community version (v1.7).
(see viewtopic.php?p=13056#p13056)
I Have in my todo list to port the changes over the latest community version (v1.24), but as you might have seen, I haven’t been able to touch any code for a while now (professional and family reasons).
If you can help, that would be a nice place to start… 
Regards,
Pedro