Apple has released the first beta versions of iOS 12.1.1, macOS Mojave 10.14.2, and tvOS 12.1.1 for users enrolled in the respective developer beta testing programs.
Typically developer beta builds are released first, and public beta builds arrive soon after.
The latest beta builds of various Apple operating systems arrive just a day after the final releases of iOS 12.1 and MacOS Mojave 10.14.1 were made available to the general public.
If you’re actively enrolled in the iOS beta program, you can find iOS 12.1.1 beta 1 available to download now from the Settings app Software Update section. The minor point release likely signifies the beta build will aim to address any bugs or security issues identified in iOS 12.1 final. One notable change in iOS 12.1.1 is that the Facetime flip camera button is back on the main Facetime screen rather than tucked behind the nondescript three-period button.
For Mac users enrolled in the macOS beta testing program, MacOS 10.14.2 beta 1 is available from the Software Update preference panel. Presumably macOS 10.14.2 will also focus on bug fixes and security resolutions to any issues identified in the final macOS Mojave 10.14.1 release.
For users not participating in either the developer beta or public beta testing programs for Apple system software, the most recent versions of final system software builds are currently iOS 12.1 for iPhone and iPad, MacOS Mojave 10.14.1 for the Mac, and tvOS 12.1 for Apple TV.
Update: For some reason or another, macOS 10.14.2 beta 1 appears to no longer be available on the developer download site, nor in the Software Update control panel. This may be temporary, or it may be an error.