I have an original Dell, 2 rebranded Dell Sonic|blue, and one Rio. And I have loaded various versions of the riot client software, and the original mercury v.1 SW. I didn't pay close attention to which had the new code (could be HW, could be SW) because it was really easy to edit ssdp.pl to log the request, which made it easy to see and correct the problem. If it's important I can go back and isolate which device HW / SW does what.

I edited my trio.xml to set the application player line to:
menu-server="arm"
content-server="arm"

Nothing else was changed. Previously, with v0.1.6 I was running jrec, so the trio.xml file was working.

It's easy to verify the ARM server (or Ampache with ARM spoofing) is working. Just enter a query like this into your web browser (insert your IPaddress and Port):

http://IPaddress:Port/query?artist=

I saw the post that indicated Rio support may be included, and looking at the daily builds they are clearly working on supporting other devices. But it does not appear there is much interest in the Rio DAR - or at least my reason for posting is to try and flush out that interest (if it exists).