Firefox Moves to a Two-Week Release Cadence
Starting with Firefox 155 on September 1, Mozilla is doubling its release frequency to match Chrome and Edge.
Mozilla announced on August 19, 2026 that Firefox is moving from a four-week release cycle to a two-week cycle, starting with Firefox 155 on September 1 — two weeks earlier than the September 15 date originally planned under the old schedule. The change applies to both Firefox for Desktop and Firefox for Android, and every Nightly, Beta, and Release period shifts to two weeks from that point forward.
Mozilla's stated reasoning is about predictability as much as speed. The team noted it had shipped as many as six separate dot releases for a single version — Firefox 152 — under the four-week cadence, as fixes that couldn't wait for the next scheduled release kept accumulating in between cycles. A shorter cycle is meant to get completed features and fixes to users sooner by default, rather than routing an increasing share of them through unscheduled point releases.
The move brings Firefox in line with the release cadence Chrome and Microsoft Edge had already adopted earlier in 2026; Chrome shifted to two-week releases in March, and Edge followed with Edge 152 in late August. With Firefox joining them in September, all three of the browsers that make up the bulk of desktop usage now ship on the same roughly two-week rhythm, though each still maintains its own separate Extended Support Release track for organizations that want a slower-moving version.
For web developers, a faster release cadence generally means new platform features and bug fixes reach users faster, but it also means less time to catch a regression in any single beta cycle before it reaches general release — a trade-off Mozilla's own announcement acknowledges as part of why it's framing the change around predictability, not just speed. Mozilla says it will continue publishing a full schedule of upcoming release dates on its own site so that add-on developers and site owners can plan testing around the new, tighter cycle.