Is there any chance that the linuxserver team could build an Asset UPnP image?
It looks like sparklyballs (one of the contributors here?) built an image 4 years ago: https://hub.docker.com/r/sparklyballs/asset-upnp
I am currently using a docker image which has not been udpated in a year: https://hub.docker.com/r/rad1obowls/asset-upnp/dockerfile
It works fine but, this is stuck at version 6.1 when version 6.6. has been released.
I find Asset UpNP to be the best UPnP server out there, even in its free version.
The DLNA servers from plex, emby or jellyfin don’t offer any options for customising the music browsing experience (when using a phone or tablet).
Asset UPnP, on the other hand, is a lot more flexible when it comes to browsing. It helps enjoying your music!
I never had much joy with all the xxxsonic options either. I find them bloated. They offer no easy options for customizing a browsing tree.
The one thing that AssetUPnP does great is the audio format streaming. It transcodes all my FLAC and ALAC music files into WAV on the fly. This is great for those of us who have certain type of higher end music systems.