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Release Notes tell you what’s new in Firefox. As always, we welcome your feedback. You can also file a bug in Bugzilla or see the system requirements of this release.

143.0 Firefox Release

September 16, 2025

Version 143.0, first offered to Release channel users on September 16, 2025

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.

    Screenshot showing the drag and drop area for pinning tabs

  • 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.

    Screenshot showing camera preview inside permission dialog

  • 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.

    Screenshot showing file deletion prompt
    Screenshot showing setting for always deleting files

  • 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

Enterprise

Developer

  • 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.

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

All Firefox downloads