Legacy Update revives the original Windows Update website for XP, Vista, 7, and more
This is a community-run resource to help you fix the Windows Update service on earlier versions of Windows.
Since Windows XP was discontinued in 2014, followed by Windows 7 in 2020, Microsoft's support for their earlier OSes has significantly dwindled. As XP and earlier don't officially support modern security improvements, such as the SHA256 hash algorithm required by modern SSL and Authenticode certificates as of 2019, much of the internet has become inaccessible to these devices. Adding insult to injury, Microsoft actively removed many downloads for XP and earlier versions in 2020. In effect, working with these OSes is now incredibly difficult.
Windows Update provides many optional and recommended updates, in addition to drivers for your system, but Windows XP and 2000 can only install critical security updates through the built-in Automatic Updates feature. Legacy Update revives the original Windows Update website - the only way to see and install every update available for your system.
This is very cool for virtual machines and old boxes you may have lying around for use with legacy software or games.