In macOS High Sierra and earlier operating system updates show up in the Updates tab in the App Store, but not so in macOS Mojave. Now you have to make a trip to System Preferences instead. Here’s how it works.
To get to the system update option in macOS Mojave go to Apple menu > About This Mac and click Software Update. Alternately, you can go to Apple menu > System Preferences and select Software Update. If there’s a system update it’ll show up here.
You can also manage software update settings from the Software Update preferences. Check Automatically keep my Mac up to date to auto-install software updates, or leave the setting disabled to control when updates install.
Click Advanced to manage what auto-installs. You can auto-check for updates, download updates automatically, auto-install system and App Store updates, and auto-install system data files and security updates.
macOS Mojave was introduced at Apple’s annual Worldwide Developer Conference in early June and is available as a developer and public beta now. The official release is planned for this fall as a free upgrade.