Due to recent changes in Roon playback From Roon to HQPlayer is no longer possible.
Playback from Roon to StylusEP via HQPlayer protocol is also not possible.
Playback from Roon to StylusEP is still possible via Squeezebox protocol. If StylusEP does not show automatically in Roon as Squeezebox device you have to enable Squeezebox in Roon client.
Both issues are caused by Roon requiring a specific minimum version of HQPlayer (4.29). Roon requires this in order to check if the endpoint at the other end is a genuine HQPlayer program.
Since HQPlayer stopped being compatible with Euphony OS v3 somewhere around version 4.24 we cannot provide required HQPlayer binary so Roon->HQPlayer playback is broken. We will solve this issue in upcoming v4 where we can install and use the latest HQPlayer versions.
Roon->StylusEP playback via HQPlayer protocol cannot be fixed at all. Roon just doesn't want to communicate via HQP protocol with anything but the original HQPlayer. Please use StylusEP via Squeezebox protocol.