Apple has made available betas of Mac OS X 10.11.2, iOS 9.2, and tvOS 9.1 to developers. tvOS is only compatible with the new fourth-generation Apple TV with Siri Remote. (By the way, Apple is again warning that devices running iOS 9.2 can’t be restored to earlier versions of iOS.)
The new betas are available through the Software Update section of the Mac App Store and through the Apple Developer Center (https://developer.apple.com).