Mozilla has extended the support for past ESR branches Firefox 115 until September 2025 (the original support period expired in March). Firefox 115 is the latest branch that is compatible with Windows 7, 8, and 8.1 operating systems, as well as MacOS 10.12, 10.13, and 10.14. It is possible that the support for Firefox 115 may be extended beyond September, as the announcement mentions a potential consideration for additional extension in August.
According to data from February , 7.8% of Firefox users are still using Windows 7, despite Microsoft ending support for the operating system in January 2020. This percentage has decreased from 10.5% six months ago, 13.7% a year and a half ago, and 19.1% two and a half years ago. Google Chrome discontinued support for Windows 7 and Windows 8 in February 2023, making Firefox the only major browser still supporting these older Windows versions.
Additionally, the latest release Firefox 135.0.1 addressed a vulnerability (CVE-2025-1414) related to memory handling, which could potentially allow attackers to execute code by tricking users into visiting malicious websites. This update also fixes various non-security issues such as dropdown menu glitches on certain sites, scrolling problems, inability to restore closed windows and tabs from History, and issues with manually added search engines.