In addition to iOS, Apple also seeded new betas for watchOS, tvOS and OS X on Monday. The betas are available to registered developers, and can be installed via the Apple Watch app on iPhone, OTA in tvOS for those with the latest beta profile, and the update tab in the Mac App Store.
The software version numbers are watchOS 2.2.2, tvOS 9.2.2 and OS X 10.11.6, and from what we saw in the first betas, they're not adding any significant new features. The 10.11.6 change log reads "improves the stability, compatibility, and security of your Mac," and the others follow suit.