Catalina won't install, the error message states iOS 15 is required before Catalina can be installed. I
I've been on this loop for two days now, where the preferences update says there is no update needed, but the macOS 10.15.1 says version 10.15 is needed. How can I install the new update, when apple won't allow it? System preferences says my iMac is up to date with Mojave 10.14.6. So confusing, which apple never used to be.
iMac 21.5" 4K, macOS 10.14