Can't update to Catalina from Mojave 10.14.6
My system says that my software is up to date and doesn't offer an update to Catalina.
Mojave 10.14.6 (18G2022).
When I request Catalina through the app store, it says that the requested version of macOS is not available.
My MacBook Air is 13" (early 2015).
Any suggestions?
MacBook Air