The new version of the software can be downloaded directly from the Mac App Store or via the Software Update feature in the Mac App Store on any compatible Mac already running macOS High Sierra.
According to Apple's release notes, the update will improve the stability and reliability of the MacBook Pro with Touch Bar, and is recommended for all 2018 machines.
MacOS High Sierra 10.13.6 Additional Update 2 enhances the stability and reliability of MacBook Pro with Touch Bar (2018) computers, and is recommended for all users.
For detailed information about the security content of this update, visit: https://support.apple.com/kb/HT201222
It is not clear what special errors or security issues addressed in the new software, but the have build numbers of 17G2037 / 15P6805, while previous build numbers were 17G2208 / 15P6703.
Some 2018 MacBook Pro owners have experienced cracking speakers and core panel issues that may be related to the T2 chip included in the machines, so the update may address some of these issues.
Apple released a first additional update for the 2018 MacBook Pro models in July to solve a problem that caused the machines to exaggerate when they did system-intensive tasks. Today's update may potentially include further improvements to processor performance.
MacOS High Sierra comes to the end of life when Apple is preparing to trigger macOS Mojave, the latest version of MacOS, currently being beta-tested by developers and public beta testers. This is probably one of the latest updates to the High Sierra operating system.
macOS Mojave introduces more novice new features, such as a system-friendly dark mode, dynamic desktop backgrounds, Desktop Stacks to organize desktop files, Finder enhancements as a more useful Quick Look view and support for Quick Actions , and new apps like Apple News, Shares, Home and Voice Notes.
For details about what's coming in MacOS Mojave, be sure to check out our macOS Mojave roundup.