how do i update my macbook air to 10.11 or higher

Back up your data, check your applications for compatibility, and depending on which MacBook Air model you have, click on El Capitan, High Sierra, Mojave, Catalina, or Big Sur. It needs to be at least a late 2008 model to run El Capitan.

Limnos: 10.11 is not 11.

(203060)

Preparing to give away my mid-2009 MacBook Pro, I wiped the main partition and now I'm trying to reinstall OS 10.11 (which it was running before) After "verifying" the machine with my Apple ID, I get a message that OS 10.11 is "Temporarily unavailable". Any idea what's up? How long is "temporarily"?

Click here --> How to upgrade to macOS Big Sur - Apple Support

macOS Big Sur is compatible with these computers - Apple Support

Argh, I keep on getting thrown by the 10.11 and 11 thing!