Firefox on Windows 7 has been given a new lease of life, with Mozilla extending security support for Firefox 115 ESR through to the end of August 2026. That is a six-month extension beyond the previous February 2026 cutoff, and it applies to Windows 8 and 8.1 users as well. Mozilla has been candid about why this matters and, more pointedly, why it cannot last forever.
Why Mozilla Is Still Supporting Firefox on Windows 7
The short answer is user numbers. Mozilla acknowledged in a statement that there are still enough people running Windows 7 to make the extension worthwhile, at least for now. As the organisation put it: “Continuing to support it past October isn’t going to be free (backporting security fixes is already getting increasingly painful due to the divergence which naturally happens over time as an ESR goes further into its lifecycle), but there’s still enough users there that we felt it was worth doing for now at least.” That is a pragmatic, not idealistic, position — and it is worth reading carefully. Mozilla is not saying Windows 7 is safe. It is saying the cost of abandoning those users has not yet outweighed the cost of supporting them.
The extension was flagged in 2024 when Mozilla announced plans to keep supporting unsupported operating systems via the ESR channel, citing a sufficient user base. Firefox 115 ESR is the last feature release that works on Windows 7, 8, and 8.1, and users on those systems were automatically moved to the ESR channel. The same ESR 115 support extension also applies to older macOS versions.
The Real Risk of Running Firefox on Windows 7 in 2025
Here is the uncomfortable truth that Mozilla is not shying away from: Firefox security updates do not make Windows 7 safe. Microsoft ended all security support for Windows 7 on January 14, 2020. That means the underlying operating system has received no official security patches for over five years. A secure browser sitting on top of an unpatched OS is like a reinforced front door on a house with no walls. Firefox can protect your browsing to a degree, but it cannot protect the system it runs on.
Mozilla’s own language reinforces this. The organisation describes the situation as lacking “official support from Microsoft” and frames the extension as a temporary measure under re-evaluation, not a permanent commitment. The backporting process — taking security fixes developed for modern systems and adapting them for an increasingly divergent older OS — is described as “increasingly painful.” That pain only grows with time. Every month that passes, the gap between what Windows 7 can support and what modern security demands require gets wider.
What Happens After August 2026?
Mozilla has been direct in its guidance: “After that, if support is not extended, users should upgrade the operating system to continue receiving Firefox security and feature updates.” The re-evaluation language suggests another extension is possible, but nothing is guaranteed. Users who are still on Windows 7 by September 2026 without a plan face a browser that will no longer receive security patches on top of an OS that has not received them since 2020.
For users whose hardware cannot meet Windows 11’s requirements — and a significant portion of older Windows 7 machines fall into that category — Mozilla has pointed toward Linux as a practical alternative. Most mainstream Linux distributions ship with Firefox as the default browser, and many are designed to run well on older hardware. It is a meaningful suggestion from Mozilla, not a throwaway line, and it reflects a broader reality: the path forward for legacy hardware is increasingly Linux, not Windows.
Is Firefox ESR 115 still safe to use on Windows 7?
Firefox 115 ESR will continue to receive security updates from Mozilla until the end of August 2026. However, Windows 7 itself has had no official security support from Microsoft since January 14, 2020, meaning the operating system underneath the browser remains unpatched and vulnerable. Using Firefox ESR reduces browser-level risk but does not address OS-level security gaps.
What should Windows 7 users do before August 2026?
Mozilla recommends upgrading the operating system to continue receiving Firefox security and feature updates after the ESR 115 support window closes. For hardware that cannot run Windows 11, Mozilla has specifically suggested switching to Linux, where Firefox is typically the default browser and system requirements are generally lower.
Will Mozilla extend Firefox support on Windows 7 beyond August 2026?
Mozilla has said it will re-evaluate the situation, but has made no commitment to a further extension. The organisation has acknowledged that backporting security fixes is already becoming more difficult over time. Users should treat August 2026 as a firm deadline and plan accordingly rather than counting on another reprieve.
Mozilla deserves credit for being honest here — this is not a triumphant announcement but a frank admission that supporting a dead OS is hard work with a ticking clock. Firefox on Windows 7 has a runway until August 2026, and that is genuinely useful for users who need time to plan a migration. But the message underneath the extension is clear: the clock is running, and the only real fix is moving on.
This article was written with AI assistance and editorially reviewed.
Source: Windows Central
