Firefox has reached a critical milestone in its software lifecycle. Starting with version 115, the browser will no longer support Windows 7, Windows 8, or Windows 8.1. This move comes after Mozilla extended support for these older systems for nearly two years beyond its original timeline.

The decision aligns with broader industry trends, as most modern browsers have long since abandoned compatibility with Windows 7, which was released in 2009. Users running these outdated operating systems will still receive security updates through the Extended Support Release (ESR) channel until February 2026, but no further updates or new features will be provided after that date.

For those unwilling to upgrade, Mozilla recommends transitioning to Windows 10, Windows 11, or adopting a Linux-based system. Firefox remains fully supported on these platforms, ensuring users can continue accessing the latest browser innovations and security enhancements.

This shift underscores the growing pressure on legacy systems. While Windows 7 ESR patches have kept some users afloat, the absence of modern browser support leaves older machines increasingly vulnerable. The latest Firefox release, version 147, reflects the rapid evolution of web standards and security protocols—features that are no longer viable on decade-old operating systems.

The ESR channel, designed for organizations needing stability, will continue offering critical security patches for version 115 until February 2026. Beyond that, users on Windows 7, 8, or 8.1 will be cut off entirely from Firefox updates, exposing them to unpatched security risks.

What should you do now?

  • Check your OS: Verify whether you’re running Windows 7, 8, or 8.1 by navigating to Settings > System > About.
  • Upgrade or switch: If you’re on an unsupported OS, plan to migrate to Windows 10/11 or a Linux distribution before February 2026.
  • Monitor updates: Firefox ESR users should ensure their systems are updated at least annually to receive the final security patches.

Mozilla’s move is a clear signal: the era of supporting ancient operating systems with modern software is drawing to a close. For users clinging to Windows 7, the writing has been on the wall for years. Now, the time to act is here.