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.