With the help of this manual installation guide and a little hint here (Can find mcrypt in PHP 7) I managed to get Xibo CMS 1.8.11 running on Windows Server 2012 R2 with IIS 8.5.
The mcrypt is going to be dropped in 1.8.12 what I understood and have been reading on the Xibo CMS Github:
So far it seems to be working, in the coming days I’ll see if everything works fully fine and it all works well towards the screens as well. (Will post an update later on on this.)