|23 October 1999
Software Update (known as Apple Software Update on Windows) is a utility built into macOS, and installed as part of Apple's Windows software such as iTunes, iCloud, Safari, and Boot Camp, that checks for and initiates the installation of updated software.
Originally appearing in Mac OS 9, it was ported to Mac OS X to support distributing minor updates over the internet. Since Mac OS X 10.0, Software Update uses XML catalog files, and facilitates the installation of Installer packages. On Windows, Apple Software Update similarly uses XML catalog files, but rather facilitates installation of Windows Installer packages.