| Release Date | January 26, 2027 |
|---|---|
| Release Owner | TBD |
| Corresponding ESR releases | 153.11.0 · 115.49.0? |
| Nightly cycle length | 5 weeks |
| Beta cycle length | 2 weeks |
| Milestones | |
|---|---|
Deadline to request manual QAQA has been informed via a Jira ticket (Functional, Nimbus/Remote delivery or Embedded QA) about features needing manual testing — more on how to file a Jira ticket here. Test Plans and Cases also require the technical documentation, which should be attached to the ticket. |
November 26 In 18 weeks |
Deadline to request accessibility engineering reviewAccessibility engineering review has been requested (using the |
December 3 In 19 weeks |
Nightly startsThe first day of the cycle is Merge Day. After merging mozilla-central to mozilla-beta, we bump the nightly version number on mozilla-central and a new development cycle starts for Firefox. A new Firefox Nightly is shipped every 12 hours. |
December 3 In 19 weeks |
Build ready for QAFeatures with a QA request are ready for testing to assess feature quality and provide a formal test report by the end of Week 2 of the nightly cycle. |
December 11 In 20 weeks |
QA Test Plan approval dueThe QA team appreciates an earlier sign-off from the project teams. The approval milestone will be the final deadline for any feature Test Plan sign-offs. No feedback/sign-off on QAs Feature Test Plan could result in misalignment on testing scope, incomplete test coverage and invalid bugs. |
December 11 In 20 weeks |
Strings hand-off to engineeringFinal strings are handed off to Engineering to ensure they are landed before localization begins. |
January 6 In 24 weeks |
String Freeze startsIn order to ensure that our localizers have adequate time to translate strings, please make sure that all string changes have landed by end of day. |
January 6 In 24 weeks |
Draft beta release notesA draft document was created and shared internally with stakeholders to prepare our final release notes for general availability. This document initially contains a copy of our public beta release notes shipping the week after and will be enriched during the beta cycle with media and final copy. |
January 7 In 24 weeks |
Nightly QA sign-offQA signs off on the Nightly build, assessing its readiness for shipping to Beta by running a set of regression test cases and sharing a test report. |
January 7 In 24 weeks |
Merge dayThis is the day in the release cycle when we merge mozilla-central into mozilla-beta. This is the end of the development cycle for Firefox 164 and the beginning of our Beta stabilization cycle. |
January 7 In 24 weeks |
Beta 1First beta of the cycle, rolled out to our beta population. Build starts at 13:00 UTC. Stabilization work via uplifts. |
January 11 In 24.5 weeks |
Beta 2First automated beta of the cycle. It is rolled out to 100% of our beta population. Build starts at 13:00 UTC. |
January 13 In 25 weeks |
SUMO content creationUser affecting changes were identified and provided to the support.mozilla.org team. The support content for this release can now be created before release day. |
January 13 In 25 weeks |
Beta 3Build starts at 13:00 UTC. Stabilization work via uplifts. |
January 15 In 25 weeks |
Beta 4Build starts at 13:00 UTC. Stabilization work via uplifts. |
January 18 In 25.5 weeks |
Beta 5 Security bugs uplift request deadline Last beta upliftsLast beta of the cycle and thus the end of beta uplifts. This is also the deadline for security bugs uplift requests ( |
January 20 In 26 weeks |
Release notes submission deadlineAll release notes for Firefox were added to the draft document or communicated directly with the release manager. Illustrations such as screenshots and videos were provided. Final Release release notes are created by the release manager on firefox.com. |
January 21 In 26 weeks |
Release Candidate Go to buildWe merge our mozilla-beta repository to mozilla-release and close mozilla-beta until the next merge day. We then build our Release Candidate from mozilla-release. This is the build we intend to ship a week later unless we need to build another Release Candidate to fix a major quality or business critical issue. |
January 21 In 26 weeks |
Release day!Firefox 164 ships at 14:00 UTC (6 AM PT) with an initial 25% rollout. |
January 26 In 26.5 weeks |
Dot release 1Scheduled for one week after launch, this Desktop and/or Android release targets critical quality fixes and selective feature uplifts. The deadline for uplift requests is EOD on the Friday prior to go-live. Should emergency dot releases ship earlier and resolve pending issues, the Release Management team will determine if this scheduled milestone remains necessary. |
February 2 In 27.5 weeks |
| Milestones | |
|---|---|
164.0 branch is createdThe |
January 15 |
164.0 release candidate is createdThe 164.0 release candidate is created based on the |
January 15 |
Preliminary QA sign off on 164.0QA gives a preliminary sign off on 164.0. If it is green, we push the build to the External Beta Testers group. Otherwise, the dev team fixes the issues reported by QA, uplift them to the release branch and we build another Release Candidate. |
January 18 |
Final QA sign off on 164.0 Release notes readyQA gives its final sign off on 164.0. If the sign off is red, the dev team fixes the issues reported by QA, uplift them to the release branch and we build another Release Candidate. |
January 19 |
164.0 sent to Apple StoreWe submit 164.0 for review to the Apple Store. If we don`t have a working build by the end of the day, we may not ship this week. |
January 19 |
164.1 branch is createdThe |
January 22 |
164.1 release candidate is createdThe 164.1 release candidate is created based on the |
January 22 |
164.0 is shipped164.0 is shipped on the Apple Store at 3:00 AM UTC with a phased 7 days rollout: |
January 25 |
Preliminary QA sign off on 164.1QA gives a preliminary sign off on 164.1. If it is green, we push the build to the External Beta Testers group. Otherwise, the dev team fixes the issues reported by QA, uplift them to the release branch and we build another Release Candidate. |
January 25 |
Final QA sign off on 164.1 Release notes readyQA gives its final sign off on 164.1. If the sign off is red, the dev team fixes the issues reported by QA, uplift them to the release branch and we build another Release Candidate. |
January 26 |
164.1 sent to Apple StoreWe submit 164.1 for review to the Apple Store. If we don`t have a working build by the end of the day, we may not ship this week. |
January 28 |
164.1 is shipped164.1 is shipped on the Apple Store at 3:00 AM UTC with a phased 7 days rollout: |
February 1 |