Nundina › Discover calendars › Firefox Release Schedule calendar › Firefox 163 Merge DayFirefox 163 Merge Day3 December 2026 at 16:00 UTCFirefox 163 Merge Day: code moves from Nightly to Beta (Nightly becomes the next version). Planned for 2026-12-03 16:00 UTC.Firefox Release Schedule calendarMore from this calendar