14 DAY TRIAL // Apple released on Monday the first beta build of the upcoming macOS High Sierra 10.13.3 software update for supported Mac computers.
Tagged as build 17D20a, the macOS High Sierra 10.13.3 beta is now available for registered developers via the Apple Developer website and should be soon coming to public beta testers. It's been released along with the macOS 10.13.2 SDK, which provides support for developing macOS apps for Mac running macOS High Sierra 10.13.3.
Except for a known issue and the related workaround, Apple's hasn't disclosed any other information about the improvements or bug fixes implemented in the third maintenance update to the macOS High Sierra 10.13 operating system series, which, as usual, will improve the security, stability, and compatibility of your Mac.
Here's how to install macOS High Sierra 10.13.3 beta right now
Just like macOS 10.13.2 High Sierra, which was released last week with a permanent fix for the "root password" vulnerability, the macOS 10.13.3 update supports MacBook or iMac computers released in Late 2009 or later, as well as all MacBook Air, MacBook Pro, Mac mini, or Mac Pro computers released in 2010 or later.
Before installing a macOS beta update, you need to make a full backup of your computer using Time Machine. Once you've done that, you'll need to enroll your Mac in the Apple Beta Software Program. If your Mac is enrolled, you'll see the "Your computer is set to receive beta software update" message in the App Store pane in System Preferences.
To install the macOS 10.13.3 beta update on a supported Mac, you need to download and run the macOS Developer Beta Access Utility and then install it from the Updates pane in the Mac App Store. Once the first beta is installed on your Mac, you'll continue to receive further macOS 10.13.3 beta updates as they become available.