Latest Sonos App - Do not Upgrade
Just upgraded to the latest, new and improved Sonos app on my mobile phone (iPhone) and it has led to my losing my complete music library which is on a NAS.
After some discussions with support, they confirmed that this option is not available - only the commercial streaming services (and it does recognise Plex) are visible and accessible but no proprietary My Music Library.
Allegedly this will be rolled out in a future iteration, but no timeframe provided.
Beware if you are considering upgrading