29-04-2021

Firefox Version 84



< Release Management

Firefox 84 will be close to Chrome 88 in terms of version number. It seems even that Mozilla adopted 4-weeks release cycle to keep up with that. Iron Heart said on May 17, 2020 at 6:28 pm.

  • Upgrading to the new version of Firefox (84+) on Apple Silicon If you’re on a Mac computer with Apple Silicon, you will need to fully exit and restart Firefox after upgrading to Firefox 84+ in order for Firefox to run on the new architecture, which has faster performance and better battery life.
  • Firefox 84 is also the final version to support Adobe Flash. Apple recently shared a list of popular apps optimized for M1 Macs that are available in the Mac App Store, such as Pixelmator Pro.

This schedule is based on the current RapidRelease plan. Future dates may change if the process changes. Code is not always released to users on the same day as the branch migration. The release to users may be a few days later, to allow for manual testing and sign-off. Thunderbird tracks the ESR schedule column per Thunderbird release info.

Calendars

This wiki page may not always have the most current information. Please refer to one of the following calendars for up-to-date scheduling:

  • Firefox Merge/Release Dates (ICS for Thunderbird/Lightning or your calendar app) (low noise)
  • Firefox Merge/Release Full Scheduling Calendar (ICS) (highly detailed - 99.99% up to date)

Future branch dates

Quarter Soft Freeze Merge Date Nightly Beta Release Date Release ESR
Q2 20212021-05-272021-05-31Firefox 91Firefox 902021-06-01Firefox 89Firefox 78.11
2021-06-242021-06-28Firefox 92Firefox 912021-06-29Firefox 90Firefox 78.12
Q3 20212021-07-222021-07-26Firefox 93Firefox 922021-07-27Firefox 91Firefox 78.13; 91.0
2021-08-192021-08-23Firefox 94Firefox 932021-08-24Firefox 92Firefox 78.14; 91.1
2021-09-162021-09-20Firefox 95Firefox 942021-09-21Firefox 93Firefox 78.15; 91.2
Q4 20212021-10-142021-10-18Firefox 96Firefox 952021-10-19Firefox 94Firefox 91.3
2021-11-112021-11-15Firefox 97Firefox 962021-11-16Firefox 95Firefox 91.4
2021-12-092021-12-13Firefox 98Firefox 972021-12-14Firefox 96Firefox 91.5
Q1 20222022-01-202022-01-24Firefox 99Firefox 982022-01-25Firefox 97Firefox 91.6

The Nightly soft freeze is typically during the week prior to merge day. During this period high-risk patches should avoid landing until after the Nightly version bump lands on mozilla-central on merge day.

Past branch dates

More details on contents of releases can be found in the release notes archive or Wikipedia: Firefox version history.

Soft FreezeMerge DateCentralBetaRelease DateReleaseESR
2021-04-152021-04-19Firefox 90Firefox 892021-04-19Firefox 88Firefox 78.10
2021-03-182021-03-22Firefox 89Firefox 882021-03-23Firefox 87Firefox 78.9
2021-02-182021-02-22Firefox 88Firefox 872021-02-23Firefox 86Firefox 78.8
2021-01-212021-01-25Firefox 87Firefox 862021-01-26Firefox 85Firefox 78.7
2020-12-102020-12-14Firefox 86Firefox 852020-12-15Firefox 84Firefox 78.6
2020-11-122020-11-16Firefox 85Firefox 842020-11-17Firefox 83Firefox 78.5
2020-10-152020-10-19Firefox 84Firefox 832020-10-20Firefox 82Firefox 78.4
2020-09-172020-09-21Firefox 83Firefox 822020-09-22Firefox 81Firefox 78.3
2020-08-202020-08-24Firefox 82Firefox 812020-08-25Firefox 80Firefox 68.12; 78.2
2020-07-232020-07-27Firefox 81Firefox 802020-07-28Firefox 79Firefox 68.11; 78.1
2020-06-262020-06-29Firefox 80Firefox 792020-06-30Firefox 78Firefox 68.10; 78.0
2020-05-282020-06-01Firefox 79Firefox 782020-06-02Firefox 77Firefox 68.9
2020-04-302020-05-04Firefox 78Firefox 772020-05-05Firefox 76Firefox 68.8
2020-04-022020-04-06Firefox 77Firefox 762020-04-07Firefox 75Firefox 68.7
2020-03-052020-03-09Firefox 76Firefox 752020-03-10Firefox 74Firefox 68.6
2020-02-062020-02-10Firefox 75Firefox 742020-02-11Firefox 73Firefox 68.5
2020-01-022020-01-06Firefox 74Firefox 732020-01-07Firefox 72Firefox 68.4
2019-11-252019-12-02Firefox 73Firefox 722019-12-03Firefox 71Firefox 68.3
2019-10-142019-10-21Firefox 72Firefox 712019-10-22Firefox 70Firefox 68.2
2019-08-262019-09-02Firefox 71Firefox 702019-09-03Firefox 69Firefox 60.9; 68.1
2019-07-012019-07-08Firefox 70Firefox 692019-07-09Firefox 68Firefox 60.8; 68.0
2019-05-132019-05-20Firefox 69Firefox 682019-05-21Firefox 67Firefox 60.7
2019-03-112019-03-18Firefox 68Firefox 672019-03-19Firefox 66Firefox 60.6
2019-01-212019-01-28Firefox 67Firefox 662019-01-29Firefox 65Firefox 60.5
2018-12-032018-12-10Firefox 66Firefox 652018-12-11Firefox 64Firefox 60.4
2018-10-152018-10-22Firefox 65Firefox 642018-10-23Firefox 63Firefox 60.3
Merge DateCentralBetaRelease DateReleaseESR
2018-09-04Firefox 64Firefox 632018-09-05Firefox 62Firefox 60.2
2018-06-25Firefox 63Firefox 622018-06-26Firefox 61Firefox 52.9; 60.1
2018-05-07Firefox 62Firefox 612018-05-09Firefox 60Firefox 52.8; 60.0
2018-03-12Firefox 61Firefox 602018-03-13Firefox 59Firefox 52.7
2018-01-22Firefox 60Firefox 592018-01-23Firefox 58Firefox 52.6
2017-11-13Firefox 59Firefox 582017-11-14Firefox 57Firefox 52.5
2017-09-21Firefox 58Firefox 572017-09-28Firefox 56Firefox 52.4
2017-08-02Firefox 57Firefox 562017-08-08Firefox 55Firefox 52.3
2017-06-12Firefox 56Firefox 552017-06-13Firefox 54Firefox 52.2
2017-04-18Firefox 55Firefox 542017-04-19Firefox 53Firefox 45.9; 52.1
Merge DateCentralAuroraBetaRelease DateReleaseESR
2017-03-06Firefox 55Firefox 54Firefox 532017-03-07Firefox 52Firefox 45.8; 52.0
2017-01-23Firefox 54Firefox 53Firefox 522017-01-24Firefox 51Firefox 45.7
2016-12-13Firefox 50.1.0Firefox 45.6
2016-11-14Firefox 53Firefox 52Firefox 512016-11-15Firefox 50Firefox 45.5
2016-09-19Firefox 52Firefox 51Firefox 502016-09-20Firefox 49Firefox 45.4
2016-08-01Firefox 51Firefox 50Firefox 492016-08-02Firefox 48Firefox 45.3
2016-06-06Firefox 50Firefox 49Firefox 482016-06-07Firefox 47Firefox 45.2
2016-04-25Firefox 49Firefox 48Firefox 472016-04-26Firefox 46Firefox 38.8; 45.1
2016-03-07Firefox 48Firefox 47Firefox 462016-03-08Firefox 45Firefox 38.7; 45.0
2016-01-25Firefox 47Firefox 46Firefox 452016-01-26Firefox 44Firefox 38.6
2015-12-14Firefox 46Firefox 45Firefox 442015-12-15Firefox 43Firefox 38.5
2015-10-29Firefox 45Firefox 44Firefox 432015-11-03Firefox 42Firefox 38.4
2015-09-21Firefox 44Firefox 43Firefox 422015-09-22Firefox 41Firefox 38.3
2015-08-10Firefox 43Firefox 42Firefox 412015-08-11Firefox 40Firefox 38.2
2015-06-29Firefox 42Firefox 41Firefox 402015-06-30Firefox 39Firefox 31.8; 38.1
2015-06-02Firefox 38.0.5
2015-05-11*Firefox 41Firefox 40Firefox 392015-05-12*Firefox 38Firefox 31.7; 38.0
2015-03-30*Firefox 40Firefox 39Firefox 382015-03-31*Firefox 37Firefox 31.6
2015-02-23Firefox 39Firefox 38Firefox 372015-02-24Firefox 36Firefox 31.5
2015-01-12*Firefox 38Firefox 37Firefox 362015-01-13*Firefox 35Firefox 31.4
2014-11-28*Firefox 37Firefox 36Firefox 352014-12-01*Firefox 34Firefox 31.3
2014-10-13Firefox 36Firefox 35Firefox 342014-10-14Firefox 33Firefox 31.2
2014-09-02*Firefox 35Firefox 34Firefox 332014-09-02Firefox 32Firefox 24.8; 31.1
2014-07-21Firefox 34Firefox 33Firefox 322014-07-22Firefox 31Firefox 24.7; 31.0
2014-06-09Firefox 33Firefox 32Firefox 312014-06-10Firefox 30Firefox 24.6
2014-04-28Firefox 32Firefox 31Firefox 302014-04-29Firefox 29Firefox 24.5
2014-03-17Firefox 31Firefox 30Firefox 292014-03-18Firefox 28Firefox 24.4
2014-02-03*Firefox 30Firefox 29Firefox 282014-02-04*Firefox 27Firefox 24.3
2013-12-09Firefox 29Firefox 28Firefox 272013-12-10Firefox 26Firefox 24.2
2013-10-28Firefox 28Firefox 27Firefox 262013-10-29Firefox 25Firefox 17.0.10; 24.1
2013-09-16Firefox 27Firefox 26Firefox 252013-09-17Firefox 24Firefox 17.0.9; 24.0
2013-08-05Firefox 26Firefox 25Firefox 242013-08-06Firefox 23Firefox 17.0.8
2013-06-24Firefox 25Firefox 24Firefox 232013-06-25Firefox 22Firefox 17.0.7
2013-05-13Firefox 24Firefox 23Firefox 222013-05-14Firefox 21Firefox 17.0.6
2013-04-01Firefox 23Firefox 22Firefox 212013-04-02Firefox 20Firefox 17.0.5
2013-02-19*Firefox 22Firefox 21Firefox 202013-02-19Firefox 19Firefox 17.0.3
2013-01-07*Firefox 21Firefox 20Firefox 192013-01-08*Firefox 18Firefox 10.0.12; 17.0.2
2012-11-19Firefox 20Firefox 19Firefox 182012-11-20Firefox 17Firefox 10.0.11; 17.0
2012-10-08Firefox 19Firefox 18Firefox 172012-10-09Firefox 16Firefox 10.0.8
2012-08-27Firefox 18Firefox 17Firefox 162012-08-28Firefox 15Firefox 10.0.7
2012-07-16Firefox 17Firefox 16Firefox 152012-07-17Firefox 14Firefox 10.0.6
2012-06-05Firefox 16Firefox 15Firefox 142012-06-05Firefox 13Firefox 10.0.5
2012-04-24Firefox 15Firefox 14Firefox 132012-04-24Firefox 12Firefox 10.0.4
2012-03-13Firefox 14Firefox 13Firefox 122012-03-13Firefox 11Firefox 10.0.3
2012-01-31Firefox 13Firefox 12Firefox 112012-01-31Firefox 10Firefox 10.0
2011-12-20Firefox 12Firefox 11Firefox 102011-12-20Firefox 9
2011-11-08Firefox 11Firefox 10Firefox 92011-11-08Firefox 8
2011-09-27Firefox 10Firefox 9Firefox 82011-09-27Firefox 7
2011-08-16Firefox 9Firefox 8Firefox 72011-08-16Firefox 6
2011-07-05Firefox 8Firefox 7Firefox 6
2011-06-21Firefox 5
2011-05-24Firefox 7Firefox 6
2011-05-17Firefox 5
2011-04-12Firefox 6Firefox 5

*Some release dates and merge dates are rescheduled to avoid conflicts with holidays.

Notes:

  • Four week schedule starting late 2019.
  • Irregular schedule targeting six to eight week intervals, adjusting for holidays, starting 2016.
  • Six week schedule from 2011 to 2015 (with some dates delayed to avoid conflicts with holidays).
  • Firefox 5 was on a slightly different schedule. It spent five weeks each on Aurora and Beta while later releases spent six weeks on each branch.
Retrieved from 'https://wiki.mozilla.org/index.php?title=Release_Management/Calendar&oldid=1235109'

This article provides information about the changes in Firefox 84 that will affect developers. Firefox 84 was released on December 15, 2020.

Note: See also And now for … Firefox 84 on Mozilla Hacks.

Changes for web developers

Developer Tools

  • The Firefox Accessibility Inspector now supports displaying the keyboard tab order on a web page. This provides a better high-level overview of how the page will be navigated using the keyboard than tabbing through the links (bug 1654956).
Firefox Version 84

HTML

CSS

  • We've added support for complex selectors to the :not pseudo-class (bug 933562).

Removals

  • We've removed the proprietary -moz-default-appearance property values scrollbar-small (scrollbar-width: thin is used instead) and scrollbar (macOS only; scrollbar-horizontal and scrollbar-vertical are used instead) (bug 1673132).

JavaScript

  • Custom date/time formats specified as options to the Intl.DateTimeFormat() constructor can now include fractionalSecondDigits — the number of digits used to represent fractions of a second (bug 1645107).

HTTP

Security

  • Firefox now ensures that localhost URLs — such as http://localhost/ and http://dev.localhost/ — refer to the local host's loopback interface (e.g. http://127.0.0.1). As a result, resources loaded from localhost are now assumed to have been delivered securely (see Secure contexts), and also will not be treated as mixed content (bug 1220810, bug 1488740).

APIs

Firefox Free Download

  • We've added support for the PerformancePaintTiming interface of the Paint Timing API (bug 1518999).
  • The Navigator.registerProtocolHandler() method now only accepts two parameters: scheme and url. title has been removed (bug 1631464).

Download Free Mozilla Firefox Setup

Media, WebRTC, and Web Audio

  • The MediaRecorder.start() method now throws an InvalidModificationError if the number of tracks on the stream being recorded has changed (bug 1581139).

Removals

  • The application cache has been removed — developers should use the Service Worker API instead (bug 1619673).

WebAssembly

WebDriver conformance (Marionette)

  • Added chrome scope support for WebDriver:PerformActions and WebDriver:ReleaseActions (bug 1365886).
  • The new Fission-compatible API has been enabled by default now. To revert to the former API the marionette.actors.enabled preference has to be set to false (bug 1669169).
  • Fixed WebDriver:SwitchToWindow to always switch back to the top-level browsing context (bug 1305822).
  • Improved browsing context checks for WebDriver:SwitchToParentFrame (bug 1671622).
  • Fixed a hang for WebDriver:Back encountered when the currently-selected <iframe> gets unloaded (bug 1672758).

Known bugs

  • After page navigation, accessing a previously-retrieved element might not always raise a 'stale element' error, and can also lead to a 'no such element' error. To prevent this, set the marionette.actors.enabled preference to false (bug 1684827).

Changes for add-on developers

Download Firefox 84.0.1

  • The browsingData.remove() API now supports removing a subset of data types by cookieStoreId.

Older versions