You don't state what chip/processor is in your MacBook Air. First check if your Mac is compatible with macOS 27 Golden Gate. That will depend on the specific model. Apple’s current compatibility list is here:
macOS 27 Golden Gate is compatible with these computers - Apple Support
If you are not offered an update in System Settings and/or are unable to install an update downloaded via Terminal, then is likely that you are in Low data mode. Users have reported difficulty upgrading macOS over Wi-Fi in Low data mode, and that toggling that setting OFF enables them to perform a Software Update.
Turn off Low data mode
- Open System Settings
- Click on Wi-Fi
- Click on the Details button on the right side of your connected network
- Toggle the setting off
More info from Apple: Wi-Fi settings on Mac - Apple Support
If macOS 27.2 does not appear in Software Update, try the following steps in order.
- If you are using a VPN, shut it off.
- Restart your Mac.
- Go to System Settings > General > Software Update and check again. Press Command-R to refresh that settings pane, just in case.
If macOS 27 still does not appear, you can check which software updates are currently being offered to your Mac.
Open Terminal (find the app with Spotlight or in Applications > Utilities) and paste the following, then press return:
softwareupdate --list-full-installers
If macOS 27.2 appears in that list, you can download the full installer with:
softwareupdate --fetch-full-installer --full-installer-version 27.2
It has been reported that if the update attempts to install but fails before completing, and your Mac stays on the previous version of macOS, that if you are in Lockdown Mode than disabling that will allow the update to install normally.
