It is typical for Apple to release a ".0.1" update soon after releasing a major new operating system. These updates typically fix various functional issues, but this time, they also fix a security vulnerability. The security vulnerability not only affects the "26" releases of iOS and macOS, but also older versions. Apple released fixes for iOS 18 and 26, as well as for macOS back to Sonoma (14). Apple also released updates for WatchOS and tvOS, but these updates do not address any security issues. For visionOS, updates were only released for visionOS 26.