Apple has released iOS and iPadOS version 13.6.1 and macOS Catalina 10.15.6 supplemental update. Either way it's about "minor update" that arrive about a month after the previous ones and that mostly go to fix bugs and improve performance pending the arrival of "major release" which will arrive in the fall and currently in beta.
As for iOS and iPadOS, version 13.6.1 addresses an issue where unnecessary system data files may not be automatically deleted when available storage space was low. Also fixed a thermal management issue where some screens could show a green tint and one where exposure notifications could be disabled for some users.
MacOS Catalina incremental 10.15.6 update fixes a stability issue that could occur when running virtualization apps and an issue on iMac (Retina 5K, 27-inch 2020) that could cause displays to fade after waking up from standby.
To update compatible iPhones, iPads and Macs just use the appropriate menu in the settings.
Apple's smallest TOP of the range? Apple iPhone SE, on offer today by Mobzilla at 400 euros or by Media World at 479 euros.