MacRumors published a story that Apple has released the third beta of tvOS 13.4.8 to registered developers.
Apple Seeds Third Beta of tvOS 13.4.8 Update to Developers
Apple today seeded the third beta of an upcoming tvOS 13.4.8 update to developers for testing purposes, three weeks after seeding the second tvOS 13.4.8 beta and more a month after the release of the tvOS 13.4.5 update.
Apple Seeds Third Beta of tvOS 13.4.8 Update to Developers