The track mix version section identifies different versions of a song. If your release contains a specific version of a track, for example "Demo" or "Remix", you can input this info in the track mix version box.
Here are some examples of when you should make use of this section:
Remix
Live
Demo
Radio edit or extended version of your track
Alternative mixes like acoustic or instrumental versions
Please don't add ‘Bonus Track’ as a track mix version. This is deemed redundant information by stores and we will need to remove it.