The latest version of Mozilla Firefox that supports Windows XP Professional (including 64-bit editions) is , released on June 26, 2018.
To run this version, your hardware must meet these minimums: : Windows XP SP2 or SP3 . The latest version of Mozilla Firefox that supports
: Firefox 52.9.0 ESR (Extended Support Release). released on June 26
While it is the "latest" for your OS, it is no longer supported with security updates and faces significant compatibility issues on the modern web due to expired security certificates as of March 2025. 2018. To run this version