Credit for this solution goes to https://github.com/airsonic/airsonic/issues/98 from Bernardus Jansen bajansen Heerenveen https://benno.frl @BAJansen
So, I am BY NO MEANS an expert on this subject. However: 1) after you add a new transcoder under "Settings/Transcoding" for opus playback, you should be able to SAVE then, 2) go to the "Settings/Players" page and see the status of your change. If there's an error in red type, you must ADD and ENABLE THE TRANSCODER. 3) DIRECTIONS for doing so are (http://www.subsonic.org/pages/transcoding.jsp) If your libresonic directory is /var/libresonic, transcoders should be installed in /var/libresonic/transcode....