Mozilla Firefox 145

Version 145.0, first offered to Release channel users on November 11, 2025

New

• Add, edit, and delete comments to make your own notes in PDFs (summaries, questions, tasks, etc.). The comment sidebar helps you scan all your comments and quickly jump to them, which is handy for long or heavily marked-up PDFs.

• This version introduces a new phase of privacy protections, building on our research on reducing browser fingerprinting. These new defenses cut the percentage of users seen as unique almost in half, ensuring a safer and more private browsing experience in Private Browsing or when using Enhanced Tracking Protection set to Strict.

• Need a reminder of what tabs are in a group? Hover over the tab group name to get a preview of the tabs inside without opening it.

  Tab Hover Preview Video demonstration

• You can now access and manage your saved passwords right from the sidebar—no need to open a new tab or window. Stay on the page you’re on and get to your logins faster.

• Copy Link to Highlight allows users to share arbitrary sections of a page with others by copying a link through the context menu with a given selection

• The Translations feature has an improved experience when translating between languages with different script directions.

• New brand-inspired wallpapers are available for New Tab on desktop, with versions for both light and dark mode.

• With the new Open links from apps next to your active tab setting, you can have links from other applications open next to your active tab instead of at the end of the tab strip.

• Enhanced Bounce Tracking Protection’s stateless mode is now enabled by default in ETP Strict, blocking more advanced tracking techniques based on redirection

• For most Windows users, the existing desktop shortcut for launching Firefox has been replaced with the desktop launcher, a small program that will launch Firefox if it is installed, but if it is not installed will prompt the user to install Firefox. This will provide an easy installation point for Firefox users who acquire a new Windows device, where Firefox will not be installed by default, but the desktop launcher program may have synced via OneDrive or other cloud storage product. Learn more.

Fixed

• Various security fixes.

Changed

• Firefox no longer supports 32-bit Linux systems. We recommend installing the 64-bit version for continued updates and support.

• Horizontal tabs are now slightly more rounded to match the look of vertical tabs. Buttons and text inputs, including the address bar, have also been updated for consistency.

• When no extensions are installed, clicking the Extensions button now shows a message highlighting how extensions can enhance your browsing, with links to the Firefox Add-ons store.

• Local translation models are now compressed with Zstandard, reducing download sizes and on-device storage consumption. As always, all Firefox translations happen securely and privately on your local device, unlike other browsers that translate using cloud services.

• We updated default automation preferences to better support Agentic browsing, reducing the steps agents need to complete a task and chances for the agent to get stuck.

Enterprise

• You can find information about policy updates and enterprise specific bug fixes in the Firefox for Enterprise 145 Release Notes.

Developer

• Developer Information

• Microsoft UI Automation phased release rollout at 100%. Microsoft UI Automation is the new accessibility framework for Microsoft Windows. This will provide better assistive technology (AT) support and performance on Windows for current and future assistive technologies.

Web Platform

• Support has been added for the Atomics.waitAsync proposal, which is a non-blocking, asynchronous version of Atomics.wait. This allow synchronization of threads based upon the value in a shared memory location, for more details please consult our MDN documentation.

• Firefox now supports the new Integrity-Policy header for enforcing sub-resource integrity for scripts. Further implementation of this header is underway.

• Added Matroska support for the most commonly used codecs: AVC, HEVC, VP8, VP9, AV1, AAC, Opus, and Vorbis.

• The text-autospace property is now supported, allowing automatic spacing adjustments between characters from different scripts.

• The WebGPU DOM API (spec; MDN) is now available on macOS 26 (Tahoe) on Apple Silicon. For details, see the Mozilla Graphics Team Blog.

Unresolved

• On Windows, clicking tabs may not work at the very top of the screen when Firefox is maximized on a second monitor. We’re working to fix this in a future release. (Fixed in 147.0)

Community Contributions

• With the release of Firefox 145, we are pleased to welcome the developers who contributed their first code change to Firefox in this release, 5 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 Hill: 627771
  • Khalid AlHaddad: 1882718, 1975161
  • Kyler Riggs [:kylr]: 1955241, 1974265
  • Mag Mukendi: 1982207
  • Mateo Mihm: 1957059
  • Tatsunori Uchino: 1950321
  • Vlad L: 1881524