In order to give developers a chance to develop Apple TV applications in advance of the public release of the new set-top box, Apple is making a limited number of Apple TV Developer Kits available to registered Apple Developer Program members. To qualify, developers must already be members of the Apple Developer Program, must be located in one of 22 specific countries and must register to request a kit by Sept 11 at 12:00 p.m. Pacific Time. The kit includes the new Apple TV, Apple TV Remote, Power cord, Lightning to USB Cable, USB-A to USB-C Cable, and documentation. Apple notes that due to limited availability, priority will be given to teams that already have apps on the App Store, and developers will be notified of whether or not they have been selected beginning on Sept. 14.
In addition, Apple has already posted developer documentation on building apps for the new Apple TV as well as downloads and release notes of the new tvOS beta. Of particular note is that “the maximum size of an Apple TV app is limited to 200MB. Anything beyond this size needs to be packaged and loaded using on-demand resources.”