New

• On Windows, Firefox now supports running websites as web apps pinned directly to the taskbar. These are sites that you can pin and run as simplified windows directly from the taskbar without losing access to your installed add-ons. This feature is not currently available for Firefox installs from the Microsoft Store.

• Tabs can now be pinned by dragging them to the start of the tab strip, making it easier to keep important sites within reach.

  

• Copilot from Microsoft can now be chosen as a chatbot to use in the sidebar for quick access without leaving your main view.

• When a site asks for camera access, it can now be previewed inside the permission dialog. This is especially helpful when switching between multiple cameras.

  

• The Firefox address bar can now show you important dates and events. This feature supports displaying events (e.g. “Mother’s Day”) in the United States, United Kingdom, Germany, France, and Italy regions.

• Firefox has expanded its Fingerprinting Protection by reporting constant values for several more attributes of user's computers.

• When downloading a file in Private Browsing mode, Firefox now asks whether to keep or delete it after that session ends. You can adjust this behavior in Settings.

  
  

• Firefox now supports Windows UI Automation, which improves support for accessibility tools such as Windows Voice Access, Text Cursor Indicator and Narrator.

  

  This feature is part of a progressive roll out.

  What is a progressive roll out?

  Certain new Firefox features are released gradually. This means some users will see the feature before everyone does. This approach helps to get early feedback to catch bugs and improve behavior quickly, meaning more Firefox users overall have a better experience.

Fixed

• Various security fixes.

Enterprise

• You can find information about policy updates and enterprise specific bug fixes in the Firefox for Enterprise 143 Release Notes.

Developer

• Developer Information

• Unchecking the Group Similar Messages setting now prevents successive similar messages from being grouped so that all messages are displayed in the output.

• Switching between unmodified and pretty printed sources in the debugger no longer opens a new tab for pretty printed content.

• When the Inspector is focused, the eyedropper can now be launched to pick a color via the Ctrl+Shift+Y keyboard shortcut.

Web Platform

• Firefox now supports xHE-AAC audio playback on Windows 11 22H2+, macOS, and Android 9+.

• Firefox now uses an updated grid sizing algorithm to better align with the CSS Grid specification. Grid layouts that use percentage row sizes or grid items containing elements with aspect ratios (such as images) will now render correctly in more cases.

• <input type=color> now recognizes the CSS <color> format in addition to the color hex format (#ffffff). This means that color names like black and more complex strings like rgb(200 200 200) are now valid inputs. For now the value will always be converted to the hex format.

• Restrictions were removed that prevented setting the display property on <details> elements, and a ::details-content pseudo-element was added to style the expandable/collapsible contents of those elements.

Community Contributions

• With the release of Firefox 143, we are pleased to welcome the developers who contributed their first code change to Firefox in this release, 12 of whom were brand new volunteers! Please join us in thanking each of these diligent and enthusiastic individuals, and take a look at their contributions:

  • AnonAlly: 1978245
  • Balraj Dhawan: 1977903
  • Damia Vergnet: 1932365, 1979629
  • Gaétan Fine: 1177108
  • jonas.muecke: 1978226
  • Markus Probst: 1976974
  • Mason Abbruzzese: 1957214
  • Mauro V [:cheff]: 1507381, 1849937, 1872780, 1938638, 1943057, 1975093, 1976968
  • Nicolas Auvray [:Itms]: 1982134
  • overflowcat: 1978108
  • Robert: 1980791
  • s1m: 1964526

Fixed

• Dragging multiple non-adjacent tabs in horizontal tab strip mode now correctly moves them together as a group. (Bug 1982933)

• Dragging multiple tabs no longer causes toolbar unresponsiveness or visual glitches. (Bug 1984342)

• Fixed an issue where the text cursor appeared in the wrong location.. (Bug 1984045)

• Fixed a crash related to gamepad use, particularly on macOS. (Bug 1870379)

• Fixed an issue where the expand on hover feature in the sidebar would sometimes stop working. (Bug 1982129)

• Fixed a crash in KDE Plasma when using certain custom window decorations. (Bug 1984823)

• Reference link to 142.0 release notes.

New

• For users in the United States, article recommendations on your New Tab page are now grouped into topic sections like Sports, Food, and Entertainment to make stories more organized and easier to scan. You can also follow topics you’re interested in and block ones you’d prefer not to see, giving you more control over what shows up when you open a new tab.

  

  This feature is part of a progressive roll out.

  What is a progressive roll out?

  Certain new Firefox features are released gradually. This means some users will see the feature before everyone does. This approach helps to get early feedback to catch bugs and improve behavior quickly, meaning more Firefox users overall have a better experience.

• You can now see what’s behind a link before visiting it with Link Previews. Long press a link (or right-click and choose Preview Link). Previews can optionally include AI-generated key points, which are processed on your device to protect your privacy.

  Link Previews is gradually rolling out to ensure performance and quality and is now available in en-US, en-CA, en-GB, en-AU for users with more than 3 GB of available RAM.

  

  This feature is part of a progressive roll out.

  What is a progressive roll out?

  Certain new Firefox features are released gradually. This means some users will see the feature before everyone does. This approach helps to get early feedback to catch bugs and improve behavior quickly, meaning more Firefox users overall have a better experience.

• On Windows, clicking a persistent notification when Firefox is closed or restarted will now properly open Firefox with the relevant webpage, instead of just opening the main page of the website.

• ETP Strict mode now supports a flexible exception list to fix broken site features caused by tracker blocking. Exceptions are split into baseline (core functionality) and convenience (extra features), letting users choose improved site compatibility without compromising key privacy protections.

• Keep an active tab visible in a collapsed tab group
  Focus on just one tab in a group without the clutter. Your active tab stays in view, keeping things tidy even with the group collapsed.

• You can now remove extensions from the sidebar by right-clicking the extension icon and selecting Remove from Sidebar.

Fixed

• Improved the scroll speed in the bookmarks dialog to not go beyond the component area.

• Improved drag-and-drop support for blob images.

• Various security fixes.

Changed

• Improved search results from browsing history via the address bar, reducing the likelihood of duplicate results being shown.

• Improved Netmonitor so that Request Headers/Cookies/Params are displayed in the Network panel even if the request isn't finished yet.

Enterprise

• You can find information about policy updates and enterprise-specific bug fixes in the Firefox for Enterprise 142 Release Notes.

Developer

• Developer Information

• Firefox now supports the wllama API for extensions, enabling developers to integrate local language model (LLM) capabilities directly into their add-ons.

• The Debugger now offers a new setting to control whether the debugger overlay is shown during paused script execution.

  

• Firefox now supports the Prioritized Task Scheduling API, enabling developers to assign and manage task priorities.

• The Selection.getComposedRanges() API is now available, allowing developers to accurately get selected text ranges across shadow DOM boundaries.

• Added support for the URLPattern API, enabling developers to match and parse URLs using a standardized pattern syntax.

Unresolved

• Multiselecting non-contiguous tabs to drag may result in toolbar unresponsiveness or visual glitches. Dragging any single tab should resolve this. We will be landing a fix in the next dot release with Bug 1984342.

Community Contributions

• With the release of Firefox 142, we are pleased to welcome the developers who contributed their first code change to Firefox in this release, 20 of whom were brand new volunteers! Please join us in thanking each of these diligent and enthusiastic individuals, and take a look at their contributions:

  • Alex Stout: 1845523
  • Ayush Kaintura: 1963306
  • Beatriz Rizental: 1971306, 1972755
  • biyul.dev: 1931528, 1975074, 1976504
  • celenity: 1977078
  • chase.philpot: 1973697
  • Clément Brisset: 1969603
  • Connor Sabine: 1975559
  • eri: 1958853
  • Ernest Molner: 1968300
  • Jacqueline Amherst: 1961204
  • jesper: 1974023
  • Jim Gong: 1975871
  • JP Belval: 1961487
  • jtech3029: 1951724
  • Nate Gross: 1957261, 1968719
  • Richard LoRicco: 1975300
  • Rong Bao [:csmantle]: 1975201, 1975350, 1975439, 1975492, 1975643, 1975645, 1975720, 1975752, 1975849, 1975983, 1976155, 1976157, 1976225, 1976389, 1976397, 1976410, 1976699, 1976799
  • shwetank.tewari.87: 1831397
  • William: 1960743

New

• Now Firefox can help you keep your tabs organized, automatically. A local AI model identifies similar tabs, automatically organizes them into groups, and even suggests group names. Everything happens on your device to respect your privacy. Learn more here.

  

  

  This feature is part of a progressive roll out.

  What is a progressive roll out?

  Certain new Firefox features are released gradually. This means some users will see the feature before everyone does. This approach helps to get early feedback to catch bugs and improve behavior quickly, meaning more Firefox users overall have a better experience.

• Vertical tabs users can now adjust the size of the tools areas at the bottom of the sidebar. To see fewer tools and more tabs, drag down the divider line which pushes extra tools into an overflow menu.

  

• On Linux, Firefox uses less memory and no longer requires a forced restart after an update has been applied by a package manager.

• Address autofill has been enabled for users in Brazil, Spain and Japan.

• The Firefox address bar can now be used as a unit converter. The unit converter supports converting units of length, temperature, mass, force, and angular measurement, as well as timezones (e.g. “now in GMT” , “10am EDT to CET”). Selecting the result will copy it to your clipboard. Learn more here.

  

• Firefox builds in Valencian now come with a built-in Catalan (Valencian variant) dictionary for the Firefox spellchecker.

• The following languages are now available for translation:

  • Albanian
  • Gujarati
  • Hebrew
  • Hindi
  • Kannada
  • Malay
  • Malayalam
  • Persian
  • Telugu

Fixed

• Various security fixes.

Changed

• Firefox on Windows 11 now uses system provided font icons for the caption buttons, more in line with Windows 11 conventions.

Enterprise

• You can find information about policy updates and enterprise specific bug fixes in the Firefox for Enterprise 141 Release Notes.

Developer

• Developer Information

• Firefox will now also clear the back-forward-cache when receiving the Clear-Site-Data: "cache" response header.

• When creating a logpoint in the Debugger, there's now a checkbox allowing to output the stacktrace in addition to the log message in the Console.

Web Platform

• Enabled the WebGPU API (spec; MDN) on Windows. For details, see the Mozilla Graphics Team Blog.

• Implemented the closedby attribute and it's related closedBy property on dialogs indicating the types of user actions that can be used to close the associated <dialog> element.

• Support for Cookies Having Independent Partitioned State (CHIPS) is now re-enabled, allowing developers to opt a cookie into storage partitioning per top-level site.

• The HTMLElement.showPopover() and HTMLElement.togglePopover() methods now take an options.source argument referencing the popover invoker, and togglePopover() also takes a force resp. options.force argument to force the popover open or closed.

Community Contributions

• With the release of Firefox 141, we are pleased to welcome the developers who contributed their first code change to Firefox in this release, 12 of whom were brand new volunteers! Please join us in thanking each of these diligent and enthusiastic individuals, and take a look at their contributions:

  • ales.astone: 1920385, 1968910
  • Chris Vander Linden: 1888847
  • Gabriel Astorgano[:astor}: 1911190
  • Jelte Fennema: 1945951
  • Mr. Beedell, Roke Julian Lockhart (RJLB): 1969599
  • Nick Crast: 1965895
  • Sajid Anwar [:sajidanwar]: 825197, 1969770
  • Simon Wülker: 1971080
  • Skye Green [:skyevg]: 1965646
  • viet-hung.nhu: 1968288
  • wilsu: 1956211
  • наб: 1970690

Fixed

• Fixed a startup crash experienced by some Linux users with outdated NVIDIA drivers. (Bug 1978911)

• Fixed a regression that caused canvas objects to be draggable, causing web compatibility issues. (Bug 1978673)

• Fixed a crash in the Web Developer Tools panel that could occur when inspecting pages with <iframe> elements. (Bug 1975277)

• Fixed minor visual issues across the user interface. (Bug 1974269 · Bug 1976031 · Bug 1974876 · Bug 1976701)

• Firefox wouldn't start on some systems where GTK+ was built without Wayland support. (Bug 1978620)

• Fixed an issue where clicking a pinned tab could steal focus from the content area, disrupting keyboard navigation. (Bug 1977005)

• Reference link to 141.0 release notes.

Fixed

• Fixed a regression that caused issues on sites built with the Svelte framework. (Bug 1980081)

• Fixed an issue where cryptominers were not listed as blocked in Strict Tracking Protection. (Bug 1977066)

• Reference link to 141.0.2 release notes.

Fixed

• Fixed a regression that caused issues on sites built with the Svelte framework. (Bug 1980081)

• Fixed an issue where cryptominers were not listed as blocked in Strict Tracking Protection. (Bug 1977066)

• Reference link to 141.0.2 release notes.

Fixed

• Fixed a startup crash experienced by some Linux users with outdated NVIDIA drivers. (Bug 1978911)

• Fixed a regression that caused canvas objects to be draggable, causing web compatibility issues. (Bug 1978673)

• Fixed a crash in the Web Developer Tools panel that could occur when inspecting pages with <iframe> elements. (Bug 1975277)

• Fixed minor visual issues across the user interface. (Bug 1974269 · Bug 1976031 · Bug 1974876 · Bug 1976701)

• Firefox wouldn't start on some systems where GTK+ was built without Wayland support. (Bug 1978620)

• Fixed an issue where clicking a pinned tab could steal focus from the content area, disrupting keyboard navigation. (Bug 1977005)

• Reference link to 141.0 release notes.

New

• Now Firefox can help you keep your tabs organized, automatically. A local AI model identifies similar tabs, automatically organizes them into groups, and even suggests group names. Everything happens on your device to respect your privacy. Learn more here.

  

  

  This feature is part of a progressive roll out.

  What is a progressive roll out?

  Certain new Firefox features are released gradually. This means some users will see the feature before everyone does. This approach helps to get early feedback to catch bugs and improve behavior quickly, meaning more Firefox users overall have a better experience.

• Vertical tabs users can now adjust the size of the tools areas at the bottom of the sidebar. To see fewer tools and more tabs, drag down the divider line which pushes extra tools into an overflow menu.

  

• On Linux, Firefox uses less memory and no longer requires a forced restart after an update has been applied by a package manager.

• Address autofill has been enabled for users in Brazil, Spain and Japan.

• The Firefox address bar can now be used as a unit converter. The unit converter supports converting units of length, temperature, mass, force, and angular measurement, as well as timezones (e.g. “now in GMT” , “10am EDT to CET”). Selecting the result will copy it to your clipboard. Learn more here.

  

• Firefox builds in Valencian now come with a built-in Catalan (Valencian variant) dictionary for the Firefox spellchecker.

• The following languages are now available for translation:

  • Albanian
  • Gujarati
  • Hebrew
  • Hindi
  • Kannada
  • Malay
  • Malayalam
  • Persian
  • Telugu

Fixed

• Various security fixes.

Changed

• Firefox on Windows 11 now uses system provided font icons for the caption buttons, more in line with Windows 11 conventions.

Enterprise

• You can find information about policy updates and enterprise specific bug fixes in the Firefox for Enterprise 141 Release Notes.

Developer

• Developer Information

• Firefox will now also clear the back-forward-cache when receiving the Clear-Site-Data: "cache" response header.

• When creating a logpoint in the Debugger, there's now a checkbox allowing to output the stacktrace in addition to the log message in the Console.

Web Platform

• Enabled the WebGPU API (spec; MDN) on Windows. For details, see the Mozilla Graphics Team Blog.

• Implemented the closedby attribute and it's related closedBy property on dialogs indicating the types of user actions that can be used to close the associated <dialog> element.

• Support for Cookies Having Independent Partitioned State (CHIPS) is now re-enabled, allowing developers to opt a cookie into storage partitioning per top-level site.

• The HTMLElement.showPopover() and HTMLElement.togglePopover() methods now take an options.source argument referencing the popover invoker, and togglePopover() also takes a force resp. options.force argument to force the popover open or closed.

Community Contributions

• With the release of Firefox 141, we are pleased to welcome the developers who contributed their first code change to Firefox in this release, 12 of whom were brand new volunteers! Please join us in thanking each of these diligent and enthusiastic individuals, and take a look at their contributions:

  • ales.astone: 1920385, 1968910
  • Chris Vander Linden: 1888847
  • Gabriel Astorgano[:astor}: 1911190
  • Jelte Fennema: 1945951
  • Mr. Beedell, Roke Julian Lockhart (RJLB): 1969599
  • Nick Crast: 1965895
  • Sajid Anwar [:sajidanwar]: 825197, 1969770
  • Simon Wülker: 1971080
  • Skye Green [:skyevg]: 1965646
  • viet-hung.nhu: 1968288
  • wilsu: 1956211
  • наб: 1970690

Fixed

• Fixed a startup crash on Windows experienced by some users. (Bug 1974259)

• Reference link to 140.0.1 release notes.

Fixed

• Fixed text contrast issues in the sidebar with some dark themes. (Bug 1971487)

• Fixed a startup crash experienced by some users caused by DLL injection. (Bug 1973947)

• Reference link to 140.0 release notes.

New

• Vertical Tabs: You can now keep more — or fewer — pinned tabs in view for quicker access to important windows. Just drag the divider to resize your pinned tabs section.

  

• Custom Search Engines: Firefox now supports adding even more search engines. To add a custom engine, right-click a search field of a supported website and select “Add Search Engine”, or go to Settings > Search > Add (below the search shortcuts table) to manually enter a search URL.

• Firefox Extensions: Customize your toolbar with the option to remove the extensions shortcut, giving you more control over your browser. When the button is hidden, you can access the extensions panel again at any time from the Firefox menu by clicking the Extensions menu item.

• You can now unload tabs by right-clicking on a tab (or multiple selected tabs) and selecting "Unload Tab". This can speed up performance by reducing Firefox's memory and CPU usage.

• Full-Page Translations now prioritizes translating only the content near your current view, improving speed and responsiveness. Content outside your view is skipped unless you scroll to it, reducing unnecessary resource usage.

• Firefox builds in Arabic now come with a built-in Arabic dictionary for the Firefox spellchecker.

• Address autofill enabled for users in Italy, Poland, and Austria.

Fixed

• Various security fixes.

Changed

• The Pocket toolbar icon, as well as the Pocket integrations on New Tab, have been removed per the service shutdown announcement.

Enterprise

• You can find information about policy updates and enterprise specific bug fixes in the Firefox for Enterprise 140 Release Notes.

Developer

• Developer Information

• Improved the search feature in the Inspector panel to help developers more effectively search the DOM of the current page. Sorting the results by the number of matching elements, support “pseudo” selector state, etc.

Web Platform

• Added platform support for aria-keyshortcuts in Linux, macOS, and Windows.

• Added support for the CookieStore API, an asynchronous cookie API for scripts running in HTML documents and service workers.

• Added support for the Custom Highlight API, which allows styling arbitrary text ranges. Support for text-decoration is not included and is planned for an upcoming release.

• Added support for the pointerrawupdate event. This event provides lower-latency access to pointer movements by firing as soon as the pointer data is available, typically before the main pointermove event. Unlike pointermove, it performs an additional hit test to determine the target and fires more frequently, which may impact performance even if only a listener is added. This event is intended for applications that require high-precision input handling and cannot achieve smooth interaction using coalesced pointermove events alone.

• Service Workers are now available in Private Browsing Mode. This enhancement builds on our efforts to support IndexedDB and the DOM Cache API in Private Browsing through encrypted storage. With this change, more websites, especially those that rely on background tasks, will be able to benefit from Service workers.

• Firefox now applies a uniform user agent (UA) style to <h1> elements, regardless of whether they are used inside <article>, <aside>, <nav>, or <section>.

• Firefox will now escape less-than (<) and greater-than (>) symbols when serializing HTML attributes, making certain mXSS attacks on websites more difficult.

Unresolved

• Users with certain dark themes may experience issues with text contrast in the sidebar. A workaround is to use the built-in dark theme or the system theme
  This is tracked under Bug 1971487 and a fix will follow in a later release. (Fixed in 140.0.1)

Community Contributions

• With the release of Firefox 140, we are pleased to welcome the developers who contributed their first code change to Firefox in this release, 18 of whom were brand new volunteers! Please join us in thanking each of these diligent and enthusiastic individuals, and take a look at their contributions:

  • Abhishek Nimalan [:animalan]: 1895919
  • jadavila9: 1852664
  • Jilvin Jacob [:jilvin]: 1902439
  • John McCann [:johnm]: 1952307
  • Jörn Loviscach: 1906974
  • Martin Pitt: 1947402, 1958325
  • Matthias Riffard: 1964530
  • Nathan Mentze:nmentz: 1951703, 1964217, 1965859
  • Patrick: 1955777
  • Peter Collingbourne: 1962497
  • Robert Kirkman: 1946405
  • Rohit Borse: 1953285
  • Sergio: 1930778
  • Tommy: 1579248, 1611813
  • vinhle000: 1950165
  • Xavier Garnier: 1950505
  • Yuto Yoshino: 1911623, 1951699, 1951708, 1960031
  • zhangyilun.0719: 1964665
  • Oleksii Segeda [:Sound]: 1967637

Fixed

• Fixed Firefox freezing when switching between apps or opening certain panels within the browser. (Bug 1969253 & Bug 1969346)

• Fixed difficult selection of drop-down menu options in the Firefox preferences page when selected via the in-page search. (Bug 1968949)

• Fixed various selection issues when triple-clicking text in some situations. (Bug 1969100 & Bug 1969432)

• Fixed an incorrect filename being used when setting an image as the desktop wallpaper on Windows. (Bug 1969793)

• Various security fixes.

• Reference link to 139.0.1 release notes.

Fixed

• Fixed graphics corruption with certain NVIDIA graphics adapters and multiple monitors running at mixed refresh rates after updating to Firefox 139. (Bug 1968876)

• Reference link to 139.0 release notes.

New

• By popular request, Full-Page Translations are now available within Firefox extension pages that start with the moz-extension:// URL scheme.

  

• The New Tab custom wallpaper (and colors) option is now available! Your own image can be uploaded as your New Tab wallpaper or any custom color can be selected - from the brightest pink to dark gray. This feature will be rolling out gradually to new users and can also be enabled immediately via Firefox Labs. Additionally, new Wallpaper images and a new Celestial category have also been added.

  

• Link Previews is currently available as an experimental feature which can be enabled via Firefox Labs in the Firefox settings. After enabling, use the Alt+Shift keyboard shortcut when hovering over a link to see the previews in action!

  

• Address autofill has now been enabled for users in Australia and India.

Fixed

• PNG images with transparency now keep their transparency when pasted into Firefox.

• The upload performance of HTTP/3 has been significantly improved, particularly on resumed connections (QUIC 0-RTT) and high-bandwidth and high-delay connections.

• Various security fixes.

Changed

• Due to recent changes in how Chrome encrypts user data on Windows, the Firefox migration wizard can no longer directly import payment methods or passwords from Chrome. However, users can still export passwords from Chrome to a CSV file and then import them into Firefox using the migration wizard or the password manager.

• The Review Checker feature is shutting down and will no longer be available after June 10, 2025.

Enterprise

• You can find information about policy updates and enterprise specific bug fixes in the Firefox for Enterprise 139 Release Notes.

Developer

• Developer Information

• Based on user requests from both Mozilla Connect and Stack Overflow, the filter setting in the Network panel is now preserved across DevTools Toolbox sessions.

• The Debugger's directory root is now scoped to the specific domain where it was set, which aligns with typical usage and avoids applying it across unrelated domains. This builds on previous improvements such as a redesigned UI and easier removal of the root setting. Setting a directory root updates the Source List to show only the selected directory and its children. Learn more

• The appearance of the paused line in the Debugger has been refined for better visibility, especially in high contrast mode.

Web Platform

• The Temporal proposal, a better version of Date, is now enabled by default in Firefox.

• Timer throttling for Workers is now supported.

• Closed <details> elements are now searchable and can be automatically expanded if found via find-in-page.

• Firefox now supports the hidden=until-found attribute, allowing content to be found via find-in-page when it's otherwise hidden by default.

• window.getSelection().toString() now correctly returns the text serialization when text is selected in a text control, improving cross-browser interoperability on some sites.

• Added support for the WebAuthn largeBlob extension.

• Added support for requestClose() to HTMLDialogElement.

• The built-in editor for contenteditable and designMode now handles collapsible white-space(s) before block boundaries and white-space sequences between visible content more consistently with Chrome. As a result, Gecko no longer inserts a padding <br> element after white-space before a block boundary, aligning behavior with other browsers.

Unresolved

• Windows users with certain NVIDIA graphics adapters and multiple monitors running at mixed refresh rates may see graphics corruption after updating to Firefox 139. As a temporary workaround, set the gfx.webrender.dcomp-win.enabled preference to false in about:config and restart Firefox. This issue will be addressed in Firefox 139.0.1.

Community Contributions

• With the release of Firefox 139, we are pleased to welcome the developers who contributed their first code change to Firefox in this release, 14 of whom were brand new volunteers! Please join us in thanking each of these diligent and enthusiastic individuals, and take a look at their contributions:

  • adhaliwal34: 1888339
  • Aidan Harris: 1960339
  • Alexander Kuleshov: 1959970
  • gene smith: 1891962
  • giulianoverrando: 1930777
  • Isaac Briandt: 1944944
  • Jason Jones: 1176600, 1689254, 1855787, 1956009, 1960383
  • Kanaru Sato [:canalun]: 1947061, 1958528, 1961558
  • keanucuco: 1855839
  • lucas.chollet: 1862235
  • Raksha Kumari: 1947278
  • Ricardo Delgado Gomez: 1815793, 1952132, 1960409
  • Sangie[:sangie50]: 1958324
  • Yakub Abdulrahman Alada: 1917908

Fixed

• Fixed a crash that could occur when viewing websites that use WebGL. (Bug 1961191)

• Fixed an issue where the browser could repeatedly crash when certain SVG effects (like blur or drop shadow) were applied to very small areas. (Bug 1924241)

• On Linux, fixed an issue where video playback would appear washed-out on Wayland when HDR support was unavailable. (Bug 1961610)

• Fixed an issue where the "Match Case" shortcut Alt+C in the find-in-page toolbar did not toggle the checkbox as expected. (Bug 1952611)

• Reference link to 138.0.1 release notes.

Fixed

• Fixed an issue which caused a blank page to be shown for Home and New Tab pages for some users. (Bug 1963537)

• Added a workaround for a bug in outlook.office.com/outlook.live.com where attachment filenames are incorrectly prefixed with UTF-8 when saved. (Bug 1961710)

• Reference link to 138.0 release notes.

New

• Profile management helps protect your privacy and stay focused by separating your online life into distinct profiles — for work, school, vacation planning, or whatever you choose. You can now name your profiles and customize them with avatars and color themes for easy recognition, then quickly switch between them — all while keeping bookmarks, tabs, and browsing history completely separate.

  

  

  This feature is part of a progressive roll out.

  What is a progressive roll out?

  Certain new Firefox features are released gradually. This means some users will see the feature before everyone does. This approach helps to get early feedback to catch bugs and improve behavior quickly, meaning more Firefox users overall have a better experience.

• Users in the United States can now trigger weather suggestions in the address bar! Simply type a weather-related term or a city name, and view the result directly in the address bar dropdown.

  

  Currently available in: United States
  

  This feature is part of a progressive roll out.

  What is a progressive roll out?

  Certain new Firefox features are released gradually. This means some users will see the feature before everyone does. This approach helps to get early feedback to catch bugs and improve behavior quickly, meaning more Firefox users overall have a better experience.

• Tab Groups, a new way to organize and take control of your tabs, is now available to all users worldwide. You can create a group by dragging one tab onto another, pausing, then dropping it. You can also now reposition a tab group on the tab bar by dragging it.

• Firefox on Windows 11 now uses acrylic-style menus for popup windows, which better match the operating system’s aesthetic.

• You can now copy links from background tabs using the tabstrip context menu on MacOS and Linux.

Fixed

• Various security fixes.

Changed

• Improved the address and credit card autofill experience to better handle forms that update dynamically as users input information. Autofill now correctly fills newly revealed fields—such as those shown after selecting a country.

• Rededicated previous color settings to Contrast Control settings. (Learn more)

Enterprise

• You can find information about policy updates and enterprise specific bug fixes in the Firefox for Enterprise 138 Release Notes.

Developer

• Developer Information

• Added support for the import map integrity field, allowing you to ensure the integrity of dynamically or statically imported modules.

• Implemented support for Error.isError, enabling brand checks to determine whether an object is an instance of Error. (Learn more)

• Added support for the error.captureStackTrace extension to improve compatibility with other browsers. (Learn more)

• A new column has been added to the Network panel to display the full path of the request URL. This enhancement makes helps developers quickly view and analyze complete request paths.

• Firefox now applies a uniform user agent (UA) style to <h1> elements, regardless of whether they are used inside <article>, <aside>, <nav>, or <section>. (Learn more)

  

  This feature is part of a progressive roll out.

  What is a progressive roll out?

  Certain new Firefox features are released gradually. This means some users will see the feature before everyone does. This approach helps to get early feedback to catch bugs and improve behavior quickly, meaning more Firefox users overall have a better experience.

Web Platform

• Added support for Import Attributes, allowing developers to specify additional metadata when importing modules.

• Applications can now set their preferred degradation method to be used when the configured frame rate and resolution cannot be maintained. (Learn more)

• Firefox now enables the cache directive for the Clear-Site-Data header, allowing websites to clear the network cache. This gives websites more control over stored data, such as clearing the cache during logout to help mitigate privacy risks. (Learn more)

Unresolved

• Due to recent changes in Chrome on Windows, some users might find that the Firefox migration wizard no longer successfully imports passwords from Chrome or Chrome-based browsers. As a workaround, you can export your passwords as a CSV file from Chrome and then import them into Firefox using either the migration wizard or the Firefox password manager.

Community Contributions

• With the release of Firefox 138, we are pleased to welcome the developers who contributed their first code change to Firefox in this release, 18 of whom were brand new volunteers! Please join us in thanking each of these diligent and enthusiastic individuals, and take a look at their contributions:

  • Abdelaziz Mokhnache: 1932626, 1950987
  • Brian Ouyang: 1950467
  • Chris Shiohama: 1953971
  • cob.bzmoz: 1947667, 1956149, 1956163
  • Cruz Hernandez: 1947000
  • erosman [:erosman]: 1869171, 1951166
  • Gautam Panakkal: 1775913, 1917910
  • Harold Camacho: 1935513, 1936819
  • Ihar Hrachyshka: 1939555
  • Jacob Wood: 1915523
  • Janik Haag: 1953297
  • Jishnu Murali Thampan: 1828113, 1947594
  • joel.mozillaosi: 1950008
  • Joshua O'Brien: 1948347, 1952022
  • Luke Taylor [:ltaylor]: 1953199, 1953206
  • Ngo Fong: 1953748
  • Sandi Vujaković [:elsandosgrande]: 1951697
  • Shane Ziegler: 1953980, 1954799, 1955586

Fixed

• Fixed file picker not being displayed when exporting passwords on macOS in about:logins for some users. (Bug 1956266)

• Fixed accessibility issues with the new PDF signature feature. (Bug 1956110 and Bug 1952571)

• Fixed an issue where using the context menu to paste in the Style Editor would insert the code twice. (Bug 1955854)

• Fixed functional regressions in our XSLT support introduced in 137. (Bug 1954841)

• Fixed a tooltip flickering issue on Windows that affected some users when hovering. (Bug 1958631)

• Fixed an issue where Firefox would not respond to clicks in some HTML5 video players. (Bug 1959251)

• Fixed an issue where radio inputs behaved incorrectly when preventDefault() was called on the click event. (Bug 1957956)

• Fixed an issue that caused some Firefox users to restart their browser multiple times to complete an update. (Bug 1959492)

• Security fix.

Changed

• Fixed an issue with DRM video playback on some sites caused by the general availability rollout of Microsoft's PlayReady hardware decryption DRM support in Firefox 137. PlayReady support is now limited to specific sites while broader compatibility continues to be tested. (Bug 1959827)

• Reference link to 137.0.1 release notes.

Unresolved

• Due to recent changes in Chrome on Windows, some users might find that the Firefox migration wizard no longer successfully imports passwords from Chrome or Chrome-based browsers. As a workaround, you can export your passwords as a CSV file from Chrome and then import them into Firefox using either the migration wizard or the Firefox password manager.

Fixed

• Fixed an issue where folder shortcuts on Windows were incorrectly treated as files during file uploads, preventing selecting files within the target folder. (Bug 1958222)

• Fixed a crash experienced by Windows users when downloading files with Qihoo 360 Total Security Antivirus software installed. (Bug 1958112)

• Fixed an occasional startup crash. (Bug 1958293)

• Reference link to 137.0 release notes.

Unresolved

• Due to recent changes in Chrome on Windows, some users might find that the Firefox migration wizard no longer successfully imports passwords from Chrome or Chrome-based browsers. As a workaround, you can export your passwords as a CSV file from Chrome and then import them into Firefox using either the migration wizard or the Firefox password manager.

New

• Tab groups begin rolling out today! Stay productive and organized with less effort by grouping related tabs together. One simple way to create a group is to drag a tab onto another, pause until you see a highlight, then drop to create the group. Groups can be named, color-coded, and are always saved. You can close a group and reopen it later.

  

  

  This feature is part of a progressive roll out.

  What is a progressive roll out?

  Certain new Firefox features are released gradually. This means some users will see the feature before everyone does. This approach helps to get early feedback to catch bugs and improve behavior quickly, meaning more Firefox users overall have a better experience.

• Firefox Address Bar Refresh 2025 - new ways to search for things new, previously viewed, and more - all from the address bar:

  Features

  Unified Search Button: A new, easy-to-access button in the address bar helps you switch between search engines and search modes with ease. This feature brings the simplicity of mobile Firefox to your desktop experience.

  

  Search Term Persistence: Now when you refine a search in the address bar, the original term sticks around, making it easier to adjust your queries and find exactly what you're looking for.

  

  Secondary Action Buttons: Suggestions for common Firefox features.

  

  Contextual Search Mode: Firefox detects if you are on a page that has search capability and offers that option for you to directly search with the page engine from the address bar. Use this option at least 2 times and Firefox will suggest adding the search engine to your Firefox.

  

  Contextual Search Engine Options: Use a Contextual Search mode option at least 2 times and Firefox will suggest adding the search engine to your Firefox so that it’s always available to you.

  

  Intuitive Search Keywords: You can access various address bar search modes with convenient and descriptive keywords (e.g. @bookmarks,@tabs,@history, @actions).

  

  

  This feature is part of a progressive roll out.

  What is a progressive roll out?

  Certain new Firefox features are released gradually. This means some users will see the feature before everyone does. This approach helps to get early feedback to catch bugs and improve behavior quickly, meaning more Firefox users overall have a better experience.

• Firefox now identifies all links in PDFs and turns them into hyperlinks.

• Support HEVC playback on Linux.

• Now you can sign PDFs without leaving Firefox. Save your signatures to re-use later.

  

  

  This feature is part of a progressive roll out.

  What is a progressive roll out?

  Certain new Firefox features are released gradually. This means some users will see the feature before everyone does. This approach helps to get early feedback to catch bugs and improve behavior quickly, meaning more Firefox users overall have a better experience.

• You can now use the Firefox address bar as a calculator. Simply type an arithmetic expression and view the result in the address bar drop-down. Clicking on this result will copy it to your clipboard.

  

  

  This feature is part of a progressive roll out.

  What is a progressive roll out?

  Certain new Firefox features are released gradually. This means some users will see the feature before everyone does. This approach helps to get early feedback to catch bugs and improve behavior quickly, meaning more Firefox users overall have a better experience.

Fixed

• Various security fixes.

Enterprise

• You can find information about policy updates and enterprise specific bug fixes in the Firefox for Enterprise 137 Release Notes.

Developer

• Developer Information

• In the Inspector Fonts panel, we now display fonts metadata, like the font version, designer, vendor, license…

  

• The Network panel now allows overriding network request responses with local files.

  

Web Platform

• Support for the SVG 2 path API is now available.

• Support for the hyphenate-limit-chars property is now available. This property enables authors to have greater control over the use of automatic hyphenation.

Unresolved

• We are investigating an increase in crashes for Windows users with Qihoo 360 security software.   (Fixed in 137.0.1)

• Due to recent changes in Chrome on Windows, some users might find that the Firefox migration wizard no longer successfully imports passwords from Chrome or Chrome-based browsers. As a workaround, you can export your passwords as a CSV file from Chrome and then import them into Firefox using either the migration wizard or the Firefox password manager.

Community Contributions

• With the release of Firefox 137, we are pleased to welcome the developers who contributed their first code change to Firefox in this release, 17 of whom were brand new volunteers! Please join us in thanking each of these diligent and enthusiastic individuals, and take a look at their contributions:

  • [:anutrix]: 1727389, 1948502
  • abe hanoka: 1930779
  • ansah: 1882102
  • Bakir Grbic: 1930780
  • cpplearner: 1610833
  • Gintaras Žulys [:gzulys]: 1634662
  • h.nuchi: 1642310
  • Hazhar Sabir: 1941949
  • James Stuckey Weber: 1949953
  • Jonathan: 1943789
  • krish.patel: 1267242
  • Phil [:phigl]: 1701557
  • qcms upstreamer: 1948768
  • Steven Novaryo: 1946679
  • Tan Junjian: 1943846
  • WANG Xuerui [:xen0n]: 1778177, 1948207

Fixed

• Fixed a bug where "Cookies and site data" and "Temporary cached files and pages" were unexpectedly enabled after updating to Firefox 136 for users with "History" and/or "Site settings" set to clear on shutdown in previous versions. (Bug 1952564)

  Affected users already on Firefox 136 can disable these settings in "Privacy & Security".

• Fixed an issue where the Primary Password prompt appeared in unexpected situations. (Bug 1946121)

• Fixed visibility issues with radio buttons on dark backgrounds. (Bug 1951930)

• Fixed high CPU usage on Windows when the screen was locked or the laptop lid was closed. (Bug 1924932)

Web Platform

• Disabled support for the CookieStore API due to compatibility concerns. The API will be enabled later once the compatibility issues have been addressed.

• Reference link to 136.0.1 release notes.

Fixed

• Fixed an issue where a cookie size limit caused problems with website cookie management when using the CookieStore API. This could cause login and other state-related issues. (Bug 1950565)

• Fixed an issue where Control/Command+L did not focus the address bar in new windows. (Bug 1947723)

• Reference link to 136.0 release notes.

Unresolved

• Users clearing "History" and/or "Site settings" on shutdown on previous versions will also have clearing "Cookies and site data" and "Temporary cached files and pages" enabled after updating to Fx136 even if they previously haven't checked these settings.
  Affected users can go to "Privacy & Security" settings directly after the upgrade and uncheck both boxes to avoid getting logged out. (Bug 1952564)

New

• You can now enable the updated Firefox sidebar in Settings > General > Browser Layout to quickly access multiple tools in one click, without leaving your main view. Sidebar tools include an AI chatbot of your choice, bookmarks, history, and tabs from devices you sync with your Mozilla account.

  

• Keep a lot of tabs open? Try our new vertical tabs layout to quickly scan your list of tabs. With vertical tabs, your open and pinned tabs appear in the sidebar instead of along the top of the browser. To turn on vertical tabs, right-click on the toolbar near the top of the browser and select Turn on Vertical Tabs. If you’ve enabled the updated sidebar, you can also go to Customize sidebar and check Vertical tabs. Early testers report feeling more organized after using vertical tabs for a few days.

  

• The Clear browsing data and cookies dialog now allows clearing saved form info separately from browsing history.

  

• Smartblock Embeds allows users to selectively unblock certain social media embeds that are blocked in ETP Strict and Private Browsing modes. Currently, support is limited to a few embed types, with more to be added in future updates.

• Firefox now upgrades page loads to HTTPS by default and gracefully falls back to HTTP if the secure connection fails. This behavior is known as HTTPS-First.

• On macOS, some background tabs will be moved to lower power cores, reducing energy usage.

• Hardware-accelerated playback of HEVC video content is now supported on macOS.

• Hardware video decoding is now enabled for AMD GPUs on Linux.

• On Linux, Firefox is now available on ARM64 (AArch64), with installation options via APT and tarballs. Flatpak support is coming soon.

• The Weather forecast on the New Tab page is expanding to additional regions, including Mexico, Brazil, Argentina, and Chile, as part of an ongoing regional rollout.

  

  This feature is part of a progressive roll out.

  What is a progressive roll out?

  Certain new Firefox features are released gradually. This means some users will see the feature before everyone does. This approach helps to get early feedback to catch bugs and improve behavior quickly, meaning more Firefox users overall have a better experience.

• Address autofill enabled for users in the United Kingdom.

  

  This feature is part of a progressive roll out.

  What is a progressive roll out?

  Certain new Firefox features are released gradually. This means some users will see the feature before everyone does. This approach helps to get early feedback to catch bugs and improve behavior quickly, meaning more Firefox users overall have a better experience.

Fixed

• Firefox will now prefer the PNG format when copying images out of Firefox, allowing the preservation of transparency.

• Various security fixes.

Changed

• For New Tab stories, the Save to Pocket action was moved from a button to the context menu along with other actions, such as Bookmark.

• The macOS DMG installer packages now use LZMA for compression, reducing download size and installation time.

• Due to recent changes in macOS Sequoia, the shortcut for completing search strings to .com addresses has been changed from Ctrl+Enter to Cmd+Enter.

Enterprise

• You can find information about policy updates and enterprise specific bug fixes in the Firefox for Enterprise 136 Release Notes.

Developer

• Developer Information

• The Developer Tools debugger editor now uses Codemirror 6, which improves performance.

Web Platform

• Added support for the Intl.DurationFormat object; this enables language-sensitive duration formatting.

• Added support for the CSS :open pseudo-class for styling elements that can be toggled “open” to display more content.

• Added support for the :has-slotted pseudo-class, allowing authors to style the contents of a <slot> element when it is not empty or not using the default value.

• Added support for the CookieStore API, an asynchronous cookie API for scripts running in HTML documents and service workers.

• Added support for ARIA elements reflection.

• Firefox now sends a referrer from meta refreshes and Refresh headers.

• Added support for sending and receiving the AV1 video codec over WebRTC. Both singlecast and simulcast are supported for sending.

• Added support for sending multiple simultaneous versions of the same source over WebRTC, commonly called simulcast, with the H264 video codec. H264 is the second video codec after VP8 to be supported for sending simulcast.

• The value plaintext-only can now be specified for the contenteditable attribute, making the raw text of an element editable but without supporting rich text formatting.

• Added support for the text replacement feature in an input field on macOS. Web content can enable/disable this using the HTML autocorrect attribute.

Unresolved

• Users clearing "History" and/or "Site settings" on shutdown on previous versions will also have clearing "Cookies and site data" and "Temporary cached files and pages" enabled after updating to Fx136 even if they previously haven't checked these settings.
  Affected users can go to "Privacy & Security" settings directly after the upgrade and uncheck both boxes to avoid getting logged out. (Bug 1952564)

Community Contributions

• With the release of Firefox 136, we are pleased to welcome the developers who contributed their first code change to Firefox in this release, 10 of whom were brand new volunteers! Please join us in thanking each of these diligent and enthusiastic individuals, and take a look at their contributions:

  • Arkadiy Tetelman: 1939981
  • asthetik: 1868306
  • carlos: 1930334
  • Jonas Haukenes [:johauke]: 1932184
  • Karan Yadav: 1007374, 1513984, 1873929, 1940223
  • Krzysztof Jan Modras [:chrmod]: 1941821
  • Meike [:mei]: 1940009
  • Mitchell Ament: 1942327
  • Nathan Teodosio :nteodosio: 1924319
  • Roland Kossel: 1927764

New

• Firefox Translations now supports more languages than ever! Pages in Simplified Chinese, Japanese, and Korean can now be translated and Russian is now available as a target language for translating into.

• The credit card autofill feature is now being gradually rolled out to all users globally.

  

  This feature is part of a progressive roll out.

  What is a progressive roll out?

  Certain new Firefox features are released gradually. This means some users will see the feature before everyone does. This approach helps to get early feedback to catch bugs and improve behavior quickly, meaning more Firefox users overall have a better experience.

• AI Chatbot access is now being gradually rolled out to all users. To use this optional feature, choose AI Chatbot from the sidebar or from Firefox Labs. Then, complete the provider selection to see the chat interface become available on the sidebar.

  

  This feature is part of a progressive roll out.

  What is a progressive roll out?

  Certain new Firefox features are released gradually. This means some users will see the feature before everyone does. This approach helps to get early feedback to catch bugs and improve behavior quickly, meaning more Firefox users overall have a better experience.

• Firefox now enforces certificate transparency, requiring web servers to provide sufficient proof that their certificates were publicly disclosed before they will be trusted. This only affects servers using certificates issued by a certificate authority in Mozilla's Root CA Program.

• Additionally, the CRLite certificate revocation checking mechanism is also being gradually rolled out, substantially improving the performance of these checks.

  

  This feature is part of a progressive roll out.

  What is a progressive roll out?

  Certain new Firefox features are released gradually. This means some users will see the feature before everyone does. This approach helps to get early feedback to catch bugs and improve behavior quickly, meaning more Firefox users overall have a better experience.

• Firefox now includes safeguards to prevent sites from abusing the history API by generating excessive history entries, which can make navigating with the back and forward buttons difficult by cluttering the history. This intervention ensures that such entries, unless interacted with by the user, are skipped when using the back and forward buttons.

• Users on macOS and Linux are now given the option to close only the current tab if the Quit keyboard shortcut is used while multiple tabs are open in the window.

Fixed

• Made improvements to the Translations feature which will reduce the likelihood that models will invent new, made-up words under some circumstances.

• Various security fixes.

Changed

• The refreshed New Tab layout previously rolled out in Firefox 134 to users in the United States is now being made available in all countries where Stories are available. It features a repositioned logo to prioritize Web Search, Shortcuts, and Recommended Stories at the top. The update also includes changes to the card UI for recommended stories and allows users with larger screens to see up to four columns for better use of space.
  

  

  This feature is part of a progressive roll out.

  What is a progressive roll out?

  Certain new Firefox features are released gradually. This means some users will see the feature before everyone does. This approach helps to get early feedback to catch bugs and improve behavior quickly, meaning more Firefox users overall have a better experience.

• The “Do Not Track” checkbox has been removed from preferences. If you wish to ask websites to respect your privacy, you can use the “Tell websites not to sell or share my data” setting instead. This option is built on top of the Global Privacy Control (GPC).

• The "Copy Without Site Tracking" menu item was renamed to "Copy Clean Link" to help clarify expectations around what the feature does. "Copy Clean Link" is a list based approach to remove known tracking parameters from links. This option can also now be used on plain text links.

• Linux binaries are now provided in XZ format, replacing the previous BZ2 format, offering faster unpacking and smaller file sizes.

Developer

• Developer Information

• A warning is now displayed when content-visibility is used on elements where size containment does not apply.

• Introduced a new console command $$$ that allows searching the page, including within shadow roots.

• Enhancements to WebExtension debugging: Workers are now available in the Console panel’s context selector and breakpoints function correctly in content scripts.

Web Platform

• Added support for a post-quantum key exchange mechanism (mlkem768x25519) for HTTP/3.

• The attribute values which indicate the coordinates of PointerEvent may now be fractional values rather than only integers. This allows web apps to handle the events with higher-precision coordinates when the target element is transitioned by CSS and/or the viewport is zoomed.

• The behavior of mouseenter, mouseleave, pointerenter and pointerleave events was changed for improved spec compliance when the last mouseover or pointerover event target is removed.

• Added support for the WebAuthn getClientCapabilities() method.

Community Contributions

• With the release of Firefox 135, we are pleased to welcome the developers who contributed their first code change to Firefox in this release, 16 of whom were brand new volunteers! Please join us in thanking each of these diligent and enthusiastic individuals, and take a look at their contributions:

  • abdoatef.ab: 1775215
  • Arnaud Vergnet: 1930106
  • ChengYangyang: 1935611, 1937502
  • Dylan O'Toole: 1909931
  • Filipe Laíns: 1935621
  • Floria Fang: 1930885
  • Fredrik: 1922403
  • johndiamond: 1924542
  • Matt Mower: 1921634
  • Mauro B: 1921951
  • Muhammed: 1933441
  • Patrick Shannon: 1930848
  • Rubicon [:rubicon]: 1755647
  • Ruhan: 1894240
  • Toby Cathcart Burn: 1897783
  • Victor Vianna: 1935021

Fixed

• Fixed drop-down menus being unusable on some sites relying on certain mousemove event behavior. (Bug 1944191)

• Fixed scrolling to the wrong location with anchor tags in some situations. (Bug 1946899)

• Fixed being unable to restore closed windows and tabs via the History menu when upgrading from an older Firefox version. (Bug 1947503)

• Fixed broken search functionality when updating to Firefox 135 with a custom search engine with an overly-large icon installed. (Bug 1946156)

• Security fix.

• Reference link to 135.0 release notes.