MacRumors published a story that Apple has released the fourth beta of tvOS 14 to registered developers.

Apple Seeds Fourth Beta of tvOS 14 to Developers

Apple today seeded the fourth beta of an upcoming tvOS 14 update to developers for testing purposes. Designed for the fourth and fifth-generation Apple TV models, the new tvOS 14 beta comes two weeks after the release of the third beta.

  Apple Seeds Fourth Beta of tvOS 14 to Developers