Right, and they also do security releases for some older macOS and iOS releases, so even if your machine doesn't support the lates version, you can still have a secure machine. E.g., a few days ago they also put out security fixes for macOS 11 and 12, in January for iOS 12 (supporting iPhones 5s from 2013).

https://support.apple.com/en-us/HT201222