Although the shipping version of the Apple TV 4K is missing Dolby Atmos surround sound, support should be coming in a future tvOS update, according to Apple.
The lack of Atmos isn't due to a hardware restriction, and support for the standard is on the roadmap, the company told The Verge. Unlike most surround formats, Atmos asks speakers to simulate sounds in 3D space, instead of simply pumping audio to separate channels.
Apple's decision to ship without Atmos was presumably due to time constraints, since the format is already compatible in one way or another with devices like Roku players and the Xbox One S, as well as streaming services such as Netflix and Vudu. The first Netflix title to offer Atmos was this summer's "Okja."
The Apple TV is one of the few devices to support Dolby Vision, an HDR (high dynamic range) video format. It also offers HDR10.
The update is the second Apple has had to promise ahead of shipping new products on Friday. On Wednesday it admitted to a problem with Wi-Fi and LTE on the Apple Watch Series 3, and said it was working on a watchOS fix.
The Apple TV 4K starts at $179, and also features the same A10X processor found in this year's iPad Pros, which should in theory be more than powerful enough to support 4K, HDR, and 3D audio.