Sonos rarely (never) announce their development roadmap, but I hope this happens at some point.

So, +1 from me for this feature.

Hey folks,

Just wanted to let you all know that as of last night Dark Mode is available in the S2 app  There may be some delay in users seeing this update. If you’re not seeing it just yet, you may need to force-quit and reopen the app.

To enable or disable Dark Mode, open the mobile S2 Sonos app and navigate to Settings → App Preferences → Appearance.

Please note, your app and system must be on at least S2 version 13.3 to access this feature.