Older MacOS is no longer in the Apple store.
I have been updating older Macintosh Laptops. The update system in these laptops use the Apple store to get the updates. I have been through all the Apple web pages that have to do with MacOS and they all seem to point to the Apple Store. I currently support roughly about 140 Macs in the Edmon Low Library at Oklahoma State University. The largest number is Laptops ranging from 2012 MacBook Pro MacOS Catalina, 2014 MacBook Air MacOS Sierra, 2015 MacBook Air MacOS Monterey, and 2018 MacBook Air MacOS Monterey. Is there a plan to web page out with the older MacOS's out to do upgrades on older Macs?
MacBook Air