Updating 2017 MacBook Air to Catalina
I have a 2017 MacBook Air currently running Mojave 10.14.6.
I need to update to Catalina (to fix a glitch with Skype for Business, hopefully), but when I go either to the app store or System Preferences to do a software update, I get a message saying that my computer is already up to date and there is nothing to update. How can I update to Catalina?
MacBook Air 13", macOS 10.12