After releasing the Developer Beta builds for both yesterday, Apple has released the second Public Betas of iOS 10.2.1 and macOS 10.12.3 Sierra. The company has been busy this week, as it also seeded watchOS 3.1.3 Beta 1 today.
Neither of the two updates include any new front-facing features, as their version numbers would indicate. This build of iOS 10.2.1 contains a couple of known issues though. SOS is only supported in India, and if you uninstall the TV app, you won't be able to get it back. To be clear, these were both issues in earlier builds.
As usual, there's nothing in the macOS release notes that say anything about the build or what's included in it. These updates are mainly about bug fixes and stability improvements.
The only other beta that we might still see before Christmas is another tvOS 10.1.1, as that hasn't seen a new one since December 14.
If you're not on the Public Beta Program, you can sign up for it here. Once you're in, you can update your device by heading over to Settings -> General -> Software Update.