Nundina › Discover calendars › Firefox Release Schedule calendar › Firefox 159 Merge DayFirefox 159 Merge Day8 October 2026 at 16:00 UTCFirefox 159 Merge Day: code moves from Nightly to Beta (Nightly becomes the next version). Planned for 2026-10-08 16:00 UTC.Firefox Release Schedule calendarMore from this calendar