With the release of Firefox 62, Mozilla also stops providing support to Firefox 52 ESR, which is the latest version for those still using this ancient operating system. Firefox 62 comes with support for CSS variable fonts and shapes, dark mode automatically enabled for macOS users, improved scrolling performance in Android, and more.
https://www.notebookcheck.net/Firefox-62-now-available-for-download-Mozilla-no-longer-supports-Windows-XP.328928.0.html
1 of my friends is still using Firefox on Windows XP. Don't worry because he's actually using the One Core API Binaries to run a newer version of Firefox.
Interesting. And why is he still stuck with Windows XP? After all, if it's a very old computer, it would definitely run better - and be more secure - using Linux.