An app that uses the Spotify Web API to replace old versions of Taylor Swift's songs with the re-recorded Taylor's Versions of them in user-made playlists.
Users can log in using their own Spotify accounts, and then all playlists made by the user will be searched for songs from the albums that have, when published, been re-recorded (Fearless, Speak Now, Red, 1989). If any tracks from those albums are found, the new versions will be added in the previous track's position and the previous track will be removed, leaving the rest of the playlist intact.