Because Microsoft ended support for Windows XP in 2014 and Mozilla ended support for this version in 2018, using Firefox on XP today presents significant security risks. Final Version : Firefox 52.9.0 ESR.
: You must have at least Windows XP SP2 or SP3 installed to run this version. Firefox English Windows Xp
: Only the 32-bit version is compatible with Windows XP; the 64-bit version of Firefox requires Windows 7 or later. Because Microsoft ended support for Windows XP in
The latest and final version of that officially supports Windows XP (English) is Firefox 52.9.0 ESR (Extended Support Release), which was released on June 26, 2018. which was released on June 26