Nundina › Discover calendars › Firefox Release Schedule calendar › Firefox 157 Merge DayFirefox 157 Merge Day13 September 2026 at 00:00 UTCFirefox 157 Merge Day: code moves from Nightly to Beta (Nightly becomes the next version). Planned for 2026-09-13 00:00 UTC.Firefox Release Schedule calendarMore from this calendar