Apple has released a plethora of new betas to developers for testing purposes. They include new betas of macOS Sierra, iOS 10, watchOS 3, and tvOS 10. They can downloaded from the Apple Developer Center.
Members of the public can also get in on the beta testing fun via Apple’s public beta program. Finished versions of macOS Sierra, iOS 10, watchOS 3, and tvOS 10 are slated for release this fall.