A small subset of movies with Dolby Atmos support are beginning to roll out on the iTunes store for Apple TV 4K users running tvOS 12 beta 2. Apple announced the upgrade earlier this month, confirming that current owners of supported titles would receive Dolby Atmos sound for no additional charge.
The Vudu app for Apple TV 4K also supports Dolby Atmos but Netflix is yet to be updated with the same capabilities. It’s not yet known if tvOS 12 will bring Dolby Atmos support to other Apple TV products or if it will be limited to the 4K model.