What is a revision (and what it is not)

A mix revision includes changes and tweaks to the mix that usually involve modifying instrument levels or EQ, amount of ambience, FX, etc.

In general, a revision includes anything that fits in a sentence similar to “[turn up/down] this [instrument/FX] in this [part of the song]”.

A mix revision does not include adding new tracks, replacing the original audio files with new ones, changing the song structure, or any other major changes to the song.