Playlist folders can be shuffled on desktop. Please allow us to shuffle playlists on mobile.
Updated on 2020-05-27
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This has already been suggested here: https://community.spotify.com/t5/Live-Ideas/Mobile-View-amp-Shuffle-all-Tracks-in-Playlist-Folders/i...
We'd recommend heading over to that idea and adding your +VOTE and feedback there to show your support and contribute to the discussion around this. This way, you can also stay up to speed with any updates we have to pass on in the future regarding this feature.
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