Firefox 52.9.0 ESR (32-bit versions) was the last to still support the old EOL Windows XP and Vista. Firefox as of 52.0 later Releases have required Windows 7 and later to run. You will not be able to update and run a more current version by way of Firefox update.

http://archive.mozilla.org/pub/firefox/releases/52.9.0esr/win32/

To use current Firefox versions, besides installing a newer Windows you could try dual booting with a lightweight Linux distro with lighter desktop environment as heavier ones like Gnome 3 and KDE should be avoided. There are still some distros that support 32-bit CPU's if your WinXP system does not have a 64-bit CPU.

Every download has the same file name ... no version information is part of the installation file. Without (attempting to) install it, there is no way to know what version I have.

If you download from http://archive.mozilla.org/pub/firefox/releases/52.9.0esr/win32/ (just pick your language locale like en-US or such) it will be 32-bit Firefox 52.9.0 esr as in Firefox Setup 52.9.0esr.exe

ex for US English and British English. http://archive.mozilla.org/pub/firefox/releases/52.9.0esr/win32/en-US/ http://archive.mozilla.org/pub/firefox/releases/52.9.0esr/win32/en-GB/

If you are trying to download from say www.mozilla.org or www.mozilla.org/firefox/all on a system with a WinXP useragent then you will likely be served Firefox 43.0.1 and then you can do internal update to 52.9.0esr that way.

• https://www.mozilla.org/firefox/52.9.0/system-requirements/ (ESR)
• https://www.mozilla.org/firefox/52.0/system-requirements/ (Release, requires Win 7 and later)
• https://www.mozilla.org/firefox/53.0/system-requirements/ (requires Win 7 and later)
• https://www.mozilla.org/firefox/77.0.1/system-requirements/ (requires Win 7 and later)