Apple has today seeded the first betas of 2017. This is for all of their operating systems. We see seeds for iOS 10.2.1, macOS Sierra 10.12.3, tvOS 10.1.1, and watchOS 3.1.3. This is the third beta release for macOS and iOS, while it is the second for tvOS and watchOS.
With iOS 10.2.1, we likely see some bug fixes and improvements. We’re not sure of anything else. Since it’s a small update there likely isn’t anything major regarding changes to the UI.
In macOS 10.12.3, again we’re unsure what’s new. It’s likely bug fixes and security improvements. There are also no outward facing UI changes.
tvOS 10.1.1 brings bug fixes and solutions to issues that were caused with the last major update. Once again there are no major changes or anything new that was added.
Finally with watchOS 3.1.3, there are some bug fixes and performance improvements. Other than that there is nothing new.
To get these update you will need to go to the Settings app and find it within the software updates page. If you’re on a Mac you will need to go to the Mac App Store and find it there. If you’re currently not on these betas then you will need to go to the Apple Developer Center and download the profiles or installers from there.