Version 149.0, first offered to Release channel users on March 24, 2026

New

• View two pages side-by-side in a single window with the new Split View feature that makes it easier to compare information, research topics or work across two pages at once. To create a split view, select one or two tabs and choose Add to Split View or Open in Split View.

• Firefox now offers a free built-in VPN. Whether you’re using public Wi-Fi while traveling, searching for sensitive health information, or shopping for something personal, this feature gives you a simple way to stay protected. Once you sign in and turn it on, you can hide your location and IP address by routing it through a secure proxy while you browse in Firefox. You will get 50 GB of protection every month, with the option to turn it on or off for specific websites. This feature is progressively rolling out in the US, UK, Germany and France starting today.

  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.

• Many PDF files will now load significantly faster thanks to hardware acceleration.

• Firefox now automatically blocks notifications and permanently revokes permissions for any website flagged as malicious by SafeBrowsing. This prevents unsafe sites from sending background notifications to users, commonly used for ads, spam or phishing.

• You can now add a Share button to your toolbar via Customize Toolbar, making it easy to share the current tab using your Windows or macOS system sharing options.

• Address Autofill is enabled for users in Australia, India, Italy, Poland and Austria.

• Explore more of the web with new on-device translation support for Bosnian, Norwegian Bokmål, Serbian and Thai — plus improved accuracy for Croatian.

Firefox Labs

• Tab notes feature that lets you attach a short note to a web page is now available in Firefox Labs. You can use notes to remember why you opened a page, what you planned to do next or any details you want to revisit later. Please give notes a try and share your feedback on what works well and what can be improved.

Fixed

• Increased robustness of HTTP/3 upload performance for unstable network conditions.
• Various security fixes.

Changed

• The TrustPanel combines the privacy and security panels accessed from the address bar to give the user one place to check the Privacy and Security settings of the current page. Learn more.

• Security has been strengthened by tightening the requirements for JavaScript files that can be loaded in the parent process, providing additional defense in depth against potential threats.

• On Linux, Firefox will now default to the XDG portal file picker if available, rather than the GTK3 one, which is usually better integrated with the user's desktop environment, and more powerful.

• Firefox error pages have a fresh new look, with updated visuals that better match the overall feel of Firefox. The redesigned pages create a more cohesive experience while making it clearer what went wrong.

• On Windows, Firefox will use the modern Windows.Devices.Geolocation API for geolocation instead of Windows 7 location API.

Developer

• The toolbar of the Storage Inspector now has a button to delete all entries of the currently selected storage.
• Besides each CSS declaration related to a computed value shown in the Computed view there's now an icon to jump to it in the Rules view.

Web Platform

• showPicker() now supports text-based elements with an associated
• The functions xywh() and rect() were previously implemented for the clip-path and offset-path properties. They are now also available for the shape-outside property.
• The math value of the CSS font-family is now supported and used by default for MathML's $element.\; It\; enables\; Web\; developers\; to\; indicate\; special\; fonts\; with\; advanced\; math\; features\; should\; be\; used.\; Firefox\; will\; rely\; on\; the\; serif\; font\; for\; mathematics\; defined\; in\; Firefox\; preferences.$
• Added support for the HTML attribute popover="hint".
• Enabled media element pseudo-classes, such as :playing, :paused…
• Enabled the spec-compliant HTMLMediaElement.captureStream() API.
• Added support for closing popovers & dialogs with the Android Back Button, and implemented the CloseWatcher API for handling this in script.
• The new Reporting API provides a generic reporting mechanism for web applications to use to make reports available based on various platform features (for example Content Security Policy, Permissions-Policy or feature deprecation reports) in a consistent manner.

Community

• With the release of Firefox 149, we are pleased to welcome the developers who contributed their first code change to Firefox in this release, 25 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:
  • aaryamannsingh3: 1968250
  • Alex Leykin [:alexff]: 1989707
  • César Pedraza [:cpedraza]: 1933577
  • Daniel Tang: 2012556
  • Denys [:denyshon]: 1768757, 1804855, 1975076, 2010370, 2010914
  • felix: 2008777
  • Franccesco: 1984274
  • Gregor Dschung [:chkpnt]: 2004881
  • Henry Yeary: 1944835, 2010907
  • Jacob: 2014579
  • kian: 1643915
  • lucrobertvillanueva: 1988103
  • Matt M: 2012236
  • MUTHUSRIHEMADHARSHINI: 1994079
  • Nishchay [:nish]: 1945967
  • Ranvir Sahota: 1884983
  • Seva Alipov: 2000120
  • Simon: 1973209
  • Thomas Sileo: 1623654, 2011537
  • torrenceb90: 2003192
  • Tyler Thrailkill [:snowe]: 2003187, 2012756, 2013500
  • vadimhack.ru: 2016172
  • yooughtul: 1944213
  • Yung Kai [:YuK]: 2011420
  • Yvon Cognard: 1953375