Microsoft cut Windows 7 support on Edge, but Mozilla says "enough" Firefox users are using it to extend support to March 2025: "Backporting security fixes is already getting increasingly painful due to the divergence"

Mozilla is extending Firefox support for legacy versions of Windows and macOS until March 2025.

What you need to know

• Mozilla announced its plans to extend Firefox support on unsupported operating systems until March 2025.
•  The company will offer two ESR (Extended Support Release) releases, including 115 for unsupported operating systems and 128 for Windows 10 and newer. 
• Mozilla argues "enough" Firefox users are still running unsupported operating systems, including Windows 7, prompting its decision to extend support for Firefox on old devices. 

While it's apparent Microsoft is moving forward with its plans to cut support for Windows 10 on October 14, 2025, users can continue running Firefox 115 on unsupported devices, including Windows 7, 8, and 8.1, and macOS 10.12 to 10.14 as Mozilla has extended its support and will continue pushing important updates until April 1, 2025. Firefox 115.21 will also continue receiving updates until March 4, 2025.

For context, Firefox 115 is the last version of the browser that will run on the highlighted unsupported operating systems. This means attempting to install Firefox 116 on these unsupported operating systems will be futile.

In case you missed it, Mozilla announced its plans to extend Firefox's support on these unsupported operating systems in July. Before Mozilla announced the extended support, the company shipped Firefox 115 without mentioning whether it would run on unsupported operating systems, leaving concerned users in limbo about updating the browser. 

Mozilla planned to cut support for Windows 8.1 and Windows 7 in September 2024, but it changed its plans. The company offers two ESR (Extended Support Release) releases, including 115 for unsupported operating systems and 128 for Windows 10 and newer. 

Cutting support for Windows 7 would have allowed Mozilla to clean up the code base and relieved it of the responsibility of maintaining newer libraries that aren't necessarily supported on pre-Windows 10 releases. Interestingly, Mozilla claims enough Firefox users are running Windows 7, prompting it to extend support for the operating system. Microsoft's Edge browser and Google Chrome already cut support for Windows 7, perhaps giving Mozilla a competitive edge with an untapped market share. 

According to Mozilla:

"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."