In the last 2 releases of both the Mac and iOS Controller app (version 5.4 and 5.5), Spotify folders have been removed. Which is beyond baffling.
I've submitted feedback and diagnostics through Sonos and have been looking for either:
1) an update to bring folders back or
2) a source to revert back to the good ol' days of 5.3
I have over 50 playlists so having a large list is really un-helpful.