Mozilla has shortened Firefox’s major-release rhythm from four weeks to two. In its August 19 explanation, the organisation says the change is intended to deliver completed features and fixes sooner, with a more predictable schedule.
MDN’s release notes confirm that Firefox 155 shipped on September 1, 2026, the first release Mozilla identified for the new cadence.
More frequent does not mean twice as much
Mozilla explicitly says the faster rhythm does not mean twice as many features. Smaller follow-up releases can still happen when needed. The change also means support volunteers and documentation teams face a quicker turnaround.
Our take: version numbers are a calendar, not a scorecard. Judge an update by its actual release notes and what changed for you, rather than assuming a faster-moving number means a dramatically different browser.
This reports Mozilla’s release process; Geeknewz has not independently measured whether the new schedule improves reliability.