The prior releases would not have marked all locations as private. Unless they were imported via CSV with the private setting enabled they should only become marked private if you have updated the records with the privacy field set on.
The fastest fix would be to export to CSV (Locations / Manage screen under bulk actions). Set the sl_private column to 0 for the exported data, then re-import the locations with an “update duplicates” mode enabled. If you keep the lat/long intact you can check skip geocoding which will make the import a lot faster.