Seems like upnp is always enabled for deco m5 & m9, and you can't disable it. maybe something else is blocking it? inbuilt antivirus/intrusion prevention? Or maybe plex needs port forwarding?

UPnP is a bad idea and is always vulnerable for an attack. if the default being enabled is true then it's a serious matter and sad. 

You are correct that it needs port forwarding and that is what I did (port 32400). 

Appartently I am in double NAT setup.

Setup as follows:

UPC router (in bridge modus) 

DECO m9 (acting as router)

Switch

DECO M9 (connected via UTP

DECO M9 (connected via UTP)

my external IP address is x.x.15.255 while the WAN IP on my Deco App says that I am at 192.168.178.10 (while my LAN IP is 192.168.68.1).

So basicly I need to turn of the NAT setting I think, any idea?

Sorry, don't know about the UPC router...seems like it's issuing the lan address. You could try and setup deco in AP mode.

You may  want to delete your external IP address from the post!

Internetworker wrote

UPnP is a bad idea and is always vulnerable for an attack. if the default being enabled is true then it's a serious matter and sad. 

yeah, agree....any tplink rep care to comment on whether upnp can be disabled?

The problem was solved by calling UPC (again) and asking them to put the router in bridge modus (which the apparently not have done earlier).

Still keen to understand whether upnp could be turned of manually at the Deco M9?

In future updates, will plan a switch for UPnP. Then you will be able to control this feature.

Amazing that a customer can NOT disable UPNP....

Any idea when the new firmware with the UPNP switch will be released???

I experience more and more firmware/software shortcomings. My patience is not endless. Competition looks more attractive every day.

@TP-Link Deco 

Hi any news about the new firware (for deco m9 plus V2)?

Tks