Allegedly, Apple has re-written their Atmos Render engine, both on iOS and, somehow, on tvOS (Apple TV). No official word from Apple, but my understanding is this twitter account is someone familiar with pulling apart firmware updates to find what’s new. I personally am noticing slightly better clarity and positioning on headphones playing one of Jennifer Athena Galatia’s demo albums (the Hubble Deep Field one). Can’t say I have noticed too much of a change on the Apple TV side however.