I opened Software Update in System Settings, but found there was no macOS 27 update,why? My Mac model is MacBook Air M4.
Your M4 MacBook Air should support macOS 27, so the model itself shouldn’t be the problem.
I’d try checking System Settings > General > Software Update again after restarting the Mac. Also make sure you’re connected to the internet and that your Mac isn’t set to delay or restrict major updates.
If you’re currently on a beta version, that can also affect what update appears. Check Software Update > Beta Updates and see whether anything is enabled.
The M4 MacBook Air is compatible with macOS 27, so I’d check a few things before assuming there’s an issue with the Mac.
First, restart the Mac and check Software Update again. If you’re running an older macOS version, install any available updates first and then check again.
Also check whether Beta Updates is enabled under Software Update. If you’re on a beta channel, you may see a different update path than users running the regular release.
If macOS 27 still doesn’t appear, you can also check Apple’s macOS 27 release page to confirm which version is currently being offered for your Mac.