I have read on various sites that this should be the first thing you disable?
The last piece of software I used that needed UPNP was MSN Messenger / Windows Live Messenger for file transfer. That closed years ago. Since then I have ALWAYS disabled UPNP. Some game systems MIGHT use it (e.g. Xbox) but start with it OFF.
If you factory reset a router, then always check and turn it off. (I also turn of WPS at the same time).
20 years of broadband connectivity since 1999 trial - Live BQM