That article is almost 3 years old. I presume D-Link has reviewed any security issues by now and has fixed them where needed.
I recommend that you phone contact your regional D-Link support office and ask for help and information regarding this. We find that phone contact has better immediate results over using email.
Let us know how it goes please.
There definitely is a need as UPNP is totally unsecure for this DNR-322L. I want to have UPNP open for a few other devices for gaming like my PS4 on my network but not for this DNR. This DNR automatically opens a hole to the internet and exposes it. That's why there have been several security patches. (see article http://www.pcworld.com/article/2045643/vulnerabilities-in-dlink-network-video-recorders-enable-remote-spying-researcher-says.html)
I want the ability to turn off UPNP for this device but leave it available for my PS4 to use on my network. The cameras I have disabled. I get access to the DNR and cameras through MyDlink.com instead of directly accessing it through my local ISP IP.
I did a search on SHODAN.IO and at one time because I had UPNP enabled it showed all my cameras and DNR as open to the internet. This is not good. i quickly disabled UPNP totally on my router and then disabled it on the cameras. I want the same ability to disable it on the DNR.
While we are on the subject
There is a problem with how it handles motion detection. It runs all the time instead of working with motion detection. Even though the setting is set for on motion event only.