Hi aloha
I currently cannot play any files. When I select the Serviio server via the amplifiers interface I am expecting the next menu to be Audio, Video, Photo. (similar to what I see on my playstation) however the listing just comes up with empty. The Denon amplifier I have is a 3808, which you correctly pointed out is from 2008. I believe that only the 3808 and the 4808 models from that year supported DLNA as they had a RJ45 network port. Except the 4808 also had wifi and could display photo's and album art. The formats that I am aware these amplifiers supported was WAV, MP3, WMA and FLAC. My amplifier is currently running its latest firmware as I find kind of check for updated regularly however I don't think they are making any more firmware updates for this (now) old model. I know my amplifier is working with a DLNA server as I have been successfully using Tversity as the DLNA server for sometime. I was hoping to switch to using Serviio as it has some nice features that Tvserity does not (series info and art). One feature that I like more than anything is that it does not crash when scanning my large collection of movies, music unlike Tversity's latest release 1.9.7.
So to quickly answer your questions
* Extensions of audio file - FLAC and MP3 however I can not browse to them
* The Denon 3808 is LAN enabled
* The latest firmware is installed
* I can successfully play internet radio and stream music from other DLNA servers, Tversity, Window Media player (not so good for large collections) etc
* Not really sure what you mean by extension. If its the profile selected in Serviio, it has correctly selected the Denon profile I lifted from you example profile (which was similar to a profile I tried before posting on this forum). I have even manually selected the profile. If you mean how I control the amplifier it has a build in on screen display (LCD and TV), you can also see the same information via its built in web server. I also have successfully controlled the server via a DLNA control point such as the Android application "All Share" on my Samsung tablet and phone.
Just so you know I am in IT as I am professional developer so feel free to get me to dig into anything as I'm not afraid of getting my hands dirty

lol.
Thanks for all you help so far