Apple has updated its tvOS 11 software to developer beta 3 for testing on the Apple TV. This comes a while after the first public beta went live and even longer after the second developer beta surfaced.
If your set-top-box is registered for preview builds of the OS, head over to Settings > System > Software Updates > Update Software and hit the download button.
tvOS 11 includes minor improvements but will bring the Amazon Prime Video app to the Apple TV alongside scheduled dark and light modes for viewing times. We’ll update this article if any major changes were made in the latest build.