The year has just begun, and Apple has managed to release a few new test builds of their operating systems. Just a few days ago authorized the developers got the chance to download the third beta version of iOS 12.1.3 and macOS Mojave 10.14.3, and today cupertinos release of the fourth test build.
Traditionally, Apple does not disclose the full list of changes made in iOS 12.1.3 beta 4 and macOS Mojave 10.14.3 beta 4. However, developers who have already familiarized yourself with new test builds, confident that any major innovations in them.
Apparently, in the fourth beta versions of cupertinos focused on addressing minor issues and bugs, and enhance stability and speed on their operating system.
The exact date of release 12.1.3 iOS and macOS Mojave 10.14.3 not now. However, we can assume that the final version of the new opertional will be available to users in the very near future. This suggests significantly reduced the time between test assemblies.