Check this link
"Qlik NPrinting Engine and Server and Qlik Sense Server cannot be installed on the same computer."
Yes, I've already seen it. The problem with NPrinting is a matter of resources. For the moment I'm not using NPrinting on Production, it's only for testing purposes, so I have both working fine. But when I start to use it on Production, I will move it to another server.
In any case, do you know if I can have different version of both products? (even if they are on different servers)