I have tried to see if I could write a script to convert the old one but the playlist-D35BDBDD-1CA9-4931-86E8-C52FDD92C64A-props.sqlite files cannot be read for any meaningful info as far as I could see.
So, for anyone wanting to convert their playlists from this to SMP PM. Then there's a less painful way than adding each one.
To do it, edit the profile\js_data\playlistManager_playlist_manager.json file in something like sublime text or VSCode where you can highlight similar blocks of text and then edit multiple selections at a time.
Change the following strings or booleans for
"extension": ".ui", = > "extension": "", NOTE: ALWAYS SHOULD BE ""
"isLocked": true, = > "isLocked": false, NOTE: ALWAYS CHANGE TO false
"isAutoPlaylist": false, = > "isAutoPlaylist": true, NOTE: CHANGE THIS TO WHATEVER THE OLD ONE WAS
"query": "", = > "query": "", NOTE: DEPENDING ON ABOVE ADD A QUERY OR LEAVE FOR NORMAL PLAYLISTS
"author": "Foobar2000", = > "author": "Playlist-Manager-SMP", NOTE: ALWAYS CHANGE TO Playlist-Manager-SMP
At least this way you can edit the query manually if necessary.
Check your JSON file here first before restarting FB. https://jsonlint.com/ then open foobar2000. The playlists should now be part of SMP PM and not locked. You will have to do some editing in that but at least they'll be populated in there.