This option corresponds to the PC Foobar2000 Playback Order option, which affects the order of how tracks are played back.
Tracks, albums can be shuffled for playback, or a track repeated, or a playlist repeated...
To bring up this option, on the 'now playing' screen, tap on the 'playback order' icon on the side overlay menu.
Bringing up this option shows the current Foobar2000 'playback order' setting. Selecting another 'order' option by clicking on its radio button will set that.
Settings remain in effect until you change them, even persisting between Foobar2000 sessions on the server PC.
Since this option affects playback order, be aware of its effects on the 'now playing' controls.
So if 'repeat track' is set, for example, the track will repeat play when it gets to the end of the track. Similarly, if 'repeat playlist' is set, the playlist will repeat play when it gets to the end of the last track of that playlist.
The behavior of the play 'next' button especially will be affected by the 'playback order' setting.
