MacRumors published a story that Apple has released the fourth beta of tvOS 15.1 to registered developers.

Apple Seeds Fourth Beta of tvOS 15.1 to Developers

Apple today seeded the fourth beta of an upcoming tvOS 15.1 update, one week after seeding the third beta and three weeks after the release of tvOS 15.

Developers can download the new tvOS 15.1 beta by downloading a profile onto the ‌Apple TV‌ using Xcode.

  Apple Seeds Fourth Beta of tvOS 15.1 to Developers