The Windows XP source code was allegedly leaked online

[Max]

Originally Posted by atom0s

Not sure why you guys think nothing in XP is still being used in 10. There is no reason for Microsoft to rewrite everything from scratch every edition or even for a major edition such as 10 outside of the main core and specific libraries that directly require it. I wouldn't be surprised if we see a lot of news popping up in the near future regarding various new 0days, patches from Microsoft to fix known problems that are now going to be mainstream that were ignored for the time being, etc. with this being a public thing now.

It's not obsolete, some machines depend on legacy OS to run, switching to new OS means replacing the entire machinery and the cost runs into 5 to 6 digits or even more.