Nundina › Discover calendars › Version End-of-Life Dates calendar › Firefox 155 end of lifeFirefox 155 end of life15 September 2026Firefox 155 stops receiving security updates. Released 1 Sep 2026. Latest version 155.0.1 (4 Sep 2026). Source: endoflife.date.Version End-of-Life Dates calendarMore from this calendar