Apple has released the second beta of MacOS Mojave 10.14.3 to both development and public beta testers. The new build, comes a week after the first beta was released for the next maintenance update to MacOS. If you are a developer beta tester or have a Mac device registered in the Apple Beta Program, the update is available now. Just go to Settings>Software Update on your Mac to install it.
Repeating what has been previously mentioned on the first beta of MacOS Mojave 10.14.3, this update is very much a maintenance update. While Apple has not released any official release notes for this beta, which is usually the case, early reports suggest there is nothing on the surface that is new in the update. Rather, it is focused on bug fixes and performance improvements under-the-hood. While the release is made public, it is possible there could be some cosmetic changes here-and-there but don’t expect much in the way of new features.
As to when we can expect to see 10.14.3 go public, that will likely be another few weeks. Generally Apple releases four to six beta builds of a maintenance release before it goes public. Do the maths, that suggests a mid-January 2019 release. That timeline can shift based on bugs found and feedback from beta testers.
Finally, it is not recommended by Average Apple Guy to install beta software on your primary Mac device. You could run into a bug that impacts reliability and stability on it. It is best to run it on a dedicated beta machine if possible.