Mozilla Grants Another Lifeline to Windows 7 Users — Firefox ESR Support Extended to August 2026

For the fourth time, Mozilla has pushed back the end-of-life date for Firefox 115 ESR on legacy Windows and macOS systems, buying millions of users several more months of critical security updates.

Mozilla has once again extended security update support for Firefox 115 ESR on older operating systems — including Windows 7, Windows 8, Windows 8.1, and macOS 10.12 through 10.14 — pushing the end-of-life date from the previously scheduled February/March 2026 deadline to the end of August 2026. The extension, now reflected on Mozilla’s official support pages, marks the fourth time the organisation has renewed its commitment to users who are unable or unwilling to upgrade their ageing hardware and software.

The move is significant given that every other major browser vendor — including Google Chrome and Microsoft Edge — ended support for pre-Windows 10 systems in early 2023. Firefox 115 ESR has since stood as the sole mainstream browser still delivering patched security updates to those platforms.

A Pattern of Extensions

Firefox 115 was released in July 2023 and was designated at that time as the final feature release to support legacy Windows and older macOS builds. Rather than abandoning those users outright, Mozilla created a dedicated Firefox 115 ESR branch to continue backporting critical security patches to a frozen codebase — a commitment originally intended to last only through September 2024.

What followed was a series of deferrals driven by telemetry showing a stubborn and substantial user base still running older operating systems. Mozilla extended the deadline first to April 2025, then again to September 2025, and most recently to March 2026. The latest extension to August 2026 represents yet another six-month reprieve.

What Mozilla’s Official Page Says

Mozilla’s updated support documentation states clearly that security updates will be delivered through the ESR channel until the end of August 2026. The organisation has indicated it will re-evaluate the situation once more — this time in June 2026 — before making a final announcement on the ultimate end-of-life date.

The language leaves open the possibility of yet another extension, though Mozilla has consistently framed each reprieve as conditional rather than guaranteed. As of early March 2026, internal Firefox telemetry showed that approximately 5.33% of the browser’s user base was still running Windows 7 — a figure that, while declining, represents millions of users worldwide.

Why It Matters

Microsoft officially ended extended security support for Windows 7 and Windows 8.1 in January 2023. With no operating-system-level patches forthcoming, users on those platforms are exposed to a widening range of known vulnerabilities. While Firefox ESR cannot compensate for OS-level security gaps, it does close browser-specific attack vectors — a meaningful, if partial, protection for users with no practical path to upgrading their hardware.

Mozilla has repeatedly acknowledged the tension in its position: maintaining compatibility with unsupported operating systems is resource-intensive and, ultimately, provides diminishing security returns. Nevertheless, the organisation has chosen to prioritise access for users in lower-income regions and those with hardware constraints that make a Windows 10 or 11 upgrade impossible.

What Users Should Do Now

Mozilla continues to strongly recommend that users upgrade to Windows 10 or higher — or, where hardware does not support newer Windows versions, consider switching to a Linux-based distribution such as Linux Mint, Ubuntu LTS, or Lubuntu. Most Linux distributions ship with Firefox as the default browser and support its full release channel, including the latest features and security updates.

For users who must remain on legacy systems for the time being, Firefox 115 ESR will continue to receive automatic security updates with no action required. Those using Windows 7, 8, or 8.1 who visit the Firefox download page will automatically be directed to the compatible 115 ESR installer.

The next checkpoint to watch is June 2026, when Mozilla has said it will reassess whether to extend support beyond August or draw a definitive line under the long-running Firefox 115 ESR programme.

Sources: Mozilla Support (support.mozilla.org), Mozilla Future Releases Blog, Winaero, gHacks Tech News, TechWorm. All extension dates and user-share figures are drawn from Mozilla’s official documentation and publicly cited telemetry data.