Apple has released the fourth beta of MacOS Mojave 10.14.2 to testers today as the company continues to prepare it for public release. The update was released to developers late yesterday and is now in the public beta channel for those registered in the Apple Beta Program. It comes thirteen days after the third beta was released, an unusually long time given the one-per-week cadence Apple had been keeping lately on beta builds.
The update is to build 18C52a for those keeping score at home. If you have a Mac registered in the beta program, you should be able to find the update in Settings>Software Update it.
MacOS Mojave 10.14.2 should be considered a maintenance update. So far, in all of the beta builds, no significant feature changes have been found nor does it materially look different. Apple typically does not post Release Notes for beta builds which means everyone is a bit in the dark what is in this release. That said, with the Mac community as big as it is, if there was something new, it would have been discovered by now.
As for when we will see 10.14.2, that too is not clear. The general consensus is that it will be sometime in early-to-mid December. That isn’t confirmed by Apple but rather is based on historical beta cycles of previous Mojave and other MacOS builds.