Apple has released additional updates for its operating systems. Directly after the release of macOS 10.15.5 there is an additional security update, which you can recognise by the build number 19F101 (click on Apple > About this Mac and then on the macOS version).
For iOS there is an update to 13.5.1 which closes a gap for a jailbreak. Also watchOS (6.2.6) and tvOS (13.4.6) get updates.
Apple not only maintains current systems, but also older operating system versions. Of course they don’t get new features anymore, but they are still provided with security updates. So Mojave and High Sierra will also get appropriate adjustments. The oldest Mac that still has fresh software is an iMac Late 2009.
