Firefox Developer Edition (eo): vanhemmat versiot ja versiohistoria

Version 151.0beta, first offered to Beta channel users on April 22, 2026
Firefox Beta gets updated 3 times a week and as a consequence, the release notes for the Beta channel are updated continuously to reflect features that have reached sufficient maturity to benefit from community feedback and bug reports.
Warning: Features listed here may or may not make a final release of Firefox.
In addition to these release notes, you can follow ongoing development via the Firefox Trains website or our @FirefoxBeta Bluesky account.

New
- On macOS, URLs copied from iOS devices using Apple’s Universal Clipboard now paste correctly in Firefox.
- HTML <select> dropdowns now display as an OS-native menu on macOS, aligning their appearance and behavior with the rest of the system.
- The about:translations page is now accessible through the More Tools section of the Application Menu.
- Address Autofill is enabled for users in the Netherlands.
- With Firefox for Android you can now to swipe vertically over the toolbar to quickly see your list of tabs.
- Private Browsing Mode now has a new privacy feature that allows users to instantly clear all data from their current private session without closing the entire browser.
- Standard Enhanced Tracking Protection mode is getting increased protections against fingerprinting that limit the amount of information revealed about your computer and frustrating attempts to track you across websites.
- Local profile backups are now available on macOS and Linux, with support for restoring them across platforms.
- Local network access restrictions are now rolling out to all users. Firefox requires websites to request permission before connecting to devices on your local network or to apps and services on your device. Previously, this protection was limited to users with Enhanced Tracking Protection set to Strict.
- You can now merge multiple PDFs directly in the Firefox PDF viewer.
- Added an AI Controls section to the Firefox for Android Settings for managing AI-enhanced features.
- High dynamic range video is now supported in Firefox on Windows 10 and 11 for HDR displays connected to AMD and NVIDIA GPUs (notably this excludes Intel+NVIDIA laptops for now), work is underway to enable this feature on more GPU vendors. To use this feature you must ensure that HDR mode is enabled for the relevant displays in Windows Settings - Display. HDR videos may appear brighter in Firefox than in other browsers, which will be improved in a future release, as well as optimizations for performance.

Fixed
- Correct screen resolution reporting via JS APIs in multiple monitor setups.
- Improved color management for copied and pasted images on macOS.
- Fixed an issue on macOS where maximized Firefox windows could reopen on the wrong monitor after relaunching in multi-display setups.

Changed
- The search bar in Firefox Settings (about:preferences) is now larger and spans the full Settings column, making it easier for users to search within Settings.
- Geolocation on Windows now respects the user's Windows location permission setting, instead of overriding it, when the user grants location permission to a page. Firefox will ask users to enable the Windows permission if it is needed.
- Extensions and Themes installed in a Firefox Desktop profile directory will be restored successfully after the profile directory is moved (or restored) to a different location or a different operating system.

Developer

Web Platform
- A new CSSContainerRule.conditions property was introduced, holding an array of all container query conditions. This new property is intended to replace CSSContainerRule.containerName and CSSContainerRule.containerQuery, which only supported a single name and query, making them obsolete.
- @container rules now allow specifying a list of container query conditions instead of just one condition.
- Temporary site permissions are now correctly reflected in the Permissions API.
- Firefox improves the rendering of absolutely

Version 149.0beta, first offered to Beta channel users on February 25, 2026
Firefox Beta gets updated 3 times a week and as a consequence, the release notes for the Beta channel are updated continuously to reflect features that have reached sufficient maturity to benefit from community feedback and bug reports.
Warning: Features listed here may or may not make a final release of Firefox.
In addition to these release notes, you can follow ongoing development via the Firefox Trains website or our @FirefoxBeta Bluesky account.

New
- The WebRender layer compositor is now enabled on Windows, reducing power usage during full-screen video playback and improving WebGL/WebGPU performance.
- Many PDF files will now load significantly faster thanks to hardware acceleration.
- Address Autofill is enabled for users in Australia, India, Italy, Poland, and Austria
- 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 from Customize Toolbar. It lets you easily share the addresss of your current tab using your Windows or macOS Operating system’s sharing services.
- 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.

Fixed
- Increased robustness of HTTP/3 upload performance for unstable network conditions.

Changed
- TrustPanel combines the privacy and security panels accessed from the urlbar to give the user one place to check the privacy & security settings of the current page
- Firefox 149 tightens the security requirements for the JavaScript files that can be loaded in the parent process, to provide defense in depth against security 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.

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 <input> elements with an associated <datalist>, displaying the autofill dropdown. See documentation.
- The functions xywh() and rect() were previously already implemented for the clip-path and offset-path properties. Now they are 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 <math> 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 implement 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.

New
- Firefox now has improved support for screen readers accessing mathematical formulas embedded in PDFs.
- Firefox for Android introduces a refreshed toolbar with a modern design and improved customization support.
- Firefox for Android now includes a "Copy link text" context menu item to copy the text associated with a link.
- Added an AI Controls section to Settings for managing AI-enhanced features.
Coming in 148.0 Beta 11

Fixed
- On Windows, dragging a downloaded image to Adobe Illustrator now properly drops an image instead of the image's URL.
Developer

Web Platform
- The initial empty document is now Web-compatible: if the first navigation of a browsing context goes to about:blank, it completes synchronously and is no longer replaced by a second parser-generated document.
- Firefox now supports the Trusted Types API, which is primarily aimed at preventing cross-site scripting attacks.
- Firefox now supports the CSS shape() function, which allows defining responsive free-form shapes in properties that take shapes like clip-path. It has some advantages over the path() function, as it utilizes standard CSS syntax, supports various CSS units, and enables the use of mathematical functions.
- Firefox now supports the Sanitizer API, which provides new methods for HTML manipulation. The element.setHTML() method enables developers to insert HTML content similarly to element.innerHTML, but without the security vulnerabilities such as cross-site scripting (XSS). A complementary method, document.parseHTML(), is also available for parsing HTML safely.
- The joint iteration proposal adds new Iterator.zip and Iterator.zipKeyed methods that allow zipping together underlying iterators into an iterator over values grouped by position, similar to zip in many other languages.
- Firefox now supports the position-try-order property, which is part of CSS Anchor Positioning and allows changing the order in which position fallback options are tried.
- Service worker support for WebGPU has been added, making it available in all worker contexts. Service workers allow WebGPU to run in the background, which is particularly useful for extensions and other pages that can meaningfully share resources across multiple tabs and time periods.
- Firefox now supports the location.ancestorOrigins attribute.

New
- WebGPU support is now enabled for all macOS versions on devices with Apple Silicon processors.
- Zero copy video of hardware decoded video with AMD GPUs if supported, improving video playback performance on those systems.
- Firefox now supports the Freedesktop.org XDG Base Directory Specification.
- Firefox now supports the Safe Browsing V5 protocol and is migrating from Safe Browsing V4 to the local list mode of Safe Browsing V5 protocol.
- We've added a new feature to automatically open a Picture-in-Picture player window for a playing video in a tab if that tab is ever backgrounded. This feature was mainly contributed by a volunteer Daniele Ferla, and has recently graduated from Firefox Labs! You can turn this feature on by visiting about:settings and checking "Keep playing videos in Picture-in-Picture when switching tabs".
- Firefox 147 includes support for Compression Dictionaries, IETF RFC 9842. This can significantly reduce the number of bytes transferred to load a page in several ways. That can lead to faster pageloads, especially for users with restricted bandwidth. Several major sites are currently using this, and likely many more will in the next year.
Fixed
- A draggable button is now draggable if the drag is started from the button itself.
- Fixed an issue that prevented Windows users from selecting a tab when the cursor was at the top of the screen and Firefox was maximized on some kinds of monitors.
- For Linux GNOME Mutter users, window and rendering surface sizes were updated to match the actual pixel grid so Firefox delivers sharp rendering on fractionally scaled displays regardless of actual window size.
- Fixed a bug that made HTTP/3 requests containing non-UTF-8 header values time out or fallback to HTTP/2 after awhile.
Changed
- Firefox now uses the same quality values (q-values) in Accept-Language headers as other major browsers. The second language preference is now sent with q=0.9 instead of q=0.5, with subsequent languages decreasing by 0.1 each (minimum 0.1). This change fixes compatibility issues with some servers that incorrectly rejected requests with lower quality values.
Developer

Web Platform
- Added support for the Navigation API. This API provides the ability to initiate, intercept, and manage browser navigation actions. It is a successor to previous web platform features such as the History API and window.location, which solves their shortcomings.
- The CSS counter-* and quotes properties are now supported in the ::marker pseudo-element.
- Both CompressionStream and DecompressionStream now support the Brotli format.
- Firefox now exposes the view transition currently active on the document via the Document.activeViewTransition property.
- Firefox now supports the :active-view-transition-type selector and associated View Transitions API changes.
- CSS Module Scripts allow stylesheets to be imported using the JavaScript module system and import attributes, for more information, please see https://developer.mozilla.org/docs/Web/JavaScript/Guide/Modules#loading_non-javascript_resources.
- Support for CSS anchor positioning was added, which allows to tether elements together. The anchor-positioned elements can then have their size and position set relative to the size and location of the anchor elements to which they are bound.
- Firefox now supports Storage-Access-Headers allowing servers to opt-in into unpartitioned cookies via HTTP headers if storage-access was granted prior with the Storage-Access-API.
- Module service workers are now supported, aligning Firefox with other major browsers and improving compatibility for modern web apps.
- Implemented CSS root-font-relative units rcap, rch, rex and ric.

New
- When a website uses a file upload field (<input type=file>) without specifying what types of files it accepts, Firefox for Android will now offer additional options to make file uploads easier. Users will see choices to pick a file, take a photo, or record audio directly from their device.
- For users of the English-language versions of Firefox in France, Germany, and Italy, the address bar will now show English-language suggestions for holidays and other important dates.
- Firefox Labs is now available to all users, regardless of whether or not they choose to participate in studies or submit telemetry. That means we have more features in the hands of more people.
- macOS users now have a dedicated GPU process by default. This includes WebGPU, WebGL, and Firefox's own WebRender. With this feature enabled, fatal errors in graphics code will no longer crash the browser, and will instead transparently restart the GPU process.
- Firefox now natively supports fractional scaled displays on Linux(Wayland), making rendering more effective.
Changed
- Firefox removed support for Direct2D on Windows. If you still require Direct2D support, please use ESR 140.0 or higher.
Developer
- Unused custom properties are now hidden by default in the Rule view of the Inspector.
This not only reduces clutter, but in some cases also speeds up the rendering of the inspector panel.
- Firefox now supports sending a post-quantum (PQ) key share during the DTLS 1.3 handshake for WebRTC connections.
- Firefox now supports compressed elliptic curve points in WebCrypto.
- Firefox now supports the contrast-color() CSS function that takes a color value and returns a contrasting color. Note that the specification currently restricts the contrasting color to black or white. This limitation is expected to be removed in the future.
(Learn more)
- The Skia graphics library has been updated to improve rendering performance and compatibility.
- The @scope rule is now supported, allowing authors to restrict styling to a subtree of the DOM. This avoids having to write overly-specific selectors.
- Introduced the text-decoration-inset property, which allows authors to adjust the start and end points of line decorations.
Web Platform
- Firefox now supports the legacy -webkit-fill-available keyword as a value for the CSS width and height properties, to improve rendering of content on the web that uses this keyword. This keyword is an alias for the recently standardized stretch keyword (which isn't shipping in Firefox yet).
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.

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

- 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.
- Starting with Firefox 145, Nightly and Early-beta builds can now find previously visited pages using Semantic History Search, which lets users recall sites with natural-language and concept-based queries, all processed locally for privacy. (Learn more)
Changed
- Starting with Firefox 145, 32-bit Linux is no longer supported. We encourage users to install a 64-bit version of Firefox.
- Horizontal tabs are now slightly more round, following the look of vertical tabs. Buttons and text inputs, including the Address bar, have been updated as well for consistency.
- When a Firefox user has no extensions installed, and clicks the Extensions button on the toolbar, they will now see a message explaining how extensions can elevate their browsing experience with links to the Firefox add-ons store.
Developer

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 partially supports the new Integrity-Policy header, which is used to enforce sub-resource integrity for scripts.
- 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.

New
- You can now close a Picture-in-Picture window without pausing the video. Press Shift + Click on the close button or use Shift + Esc to exit while keeping playback uninterrupted.
- Logins in the Firefox Password Manager are now encrypted using a more modern encryption scheme, switching from 3DES-CBC to AES-256-CBC. This change only affects the local encryption of logins on the disk; logins synced through Firefox Sync are end-to-end encrypted independently and have already been using a strong encryption scheme (AES-256-GCM) previously.
- On Firefox for Android, a new translations banner now informs you of the translation status of the current webpage.
Changed
- On Windows, when opening a link from another application, Firefox will only use a window on the current virtual desktop or open a new window if needed.
- On Firefox for Android, the "Allow screenshots in private browsing" setting has been removed.
Developer
- The events tooltip in the Inspector now shows a badge besides custom events, making it easier to differentiate them from built-in events.
Web Platform
- Firefox now supports the Element.moveBefore API.
- Firefox now supports math-shift compact.
- Firefox now supports the WebGPU GPUDevice.importExternalTexture API on Windows.
- Firefox now supports PerformanceEventTiming.interactionId, allowing developers to group related input events. This enables support for the Interaction to Next Paint (INP) responsiveness metric.
- Firefox now supports the command and commandfor attributes.
- Firefox now supports the View Transitions API Level 1. The View Transitions API provides a mechanism for easily creating animated transitions between different website views.
- The resizeMode getUserMedia constraint is now available, allowing developers to crop and downscale video captured from a camera to any resolution they choose.
- Dithering is now applied when linear-gradient, conic-gradient, and radial-gradient are rendered using hardware WebRender.
- Firefox now supports the upsert proposal. This adds getOrInsert and getOrInsertComputed methods to Map and WeakMap. These methods either return the value associated with a key, or insert a default value, and then return that value, simplifying handling of cases where it's not known if a key is already present in the Map or WeakMap.
- Firefox now supports the lock() and unlock() methods of ScreenOrientation interface on Windows tablets and Android devices.
- Implemented worker transfer for RTCDataChannel.
- WebCodecs on Windows now has a batch-encoding path for VideoEncoder, improving performance with higher throughput and lower submission latency due to a larger default batch size.

New
- When a site asks for camera access, it can now be previewed in the permission dialog. This is especially helpful when switching between multiple cameras.
- Tapping a persistent notification when Firefox for Android is closed or restarted now properly opens Firefox with the relevant webpage.
- Firefox has expanded its Fingerprinting Protection by reporting constant values for several more attributes of user's computers. More Details
- When downloading a file in private browsing mode, the user will be prompted to chose whether they want to keep or delete files that are downloaded while in private browsing. This preference can also be set at about:settings.
- With Firefox for Android, you can now see your download progress in real time, with controls to pause, resume, retry, or cancel — all from the Downloads screen.
- Firefox for Android users can now configure DNS over HTTPS in the settings UI.
- Added support for running websites as web apps for Firefox on Windows. These are sites that you can pin and run as simplified windows directly from the taskbar, without loosing access to Add-ons. This feature is not available at this time for Firefox installs from the Microsoft Store.
Developer
- Unchecking the Group Similar Messages setting now prevents successive similar messages from being grouped so that all messages are displayed in the output.
Web Platform
- Firefox now supports xHE-AAC audio playback on Windows 11 22H2+, macOS, and Android 9+.
- <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.
- 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.
- 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.

New
- 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.
- 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.
Changed
- Improved search results from browsing history via the address bar, reducing the likelihood of duplicate results being shown.
Developer
- 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.
- Firefox now supports the wllama API for extensions, enabling developers to integrate local language model (LLM) capabilities directly into their add-ons.

New
- On Linux Firefox uses less memory and no longer requires a forced restart after an update has been applied by a package manager.
- Firefox builds in Valencian now come with a built-in Catalan (Valencian variant) dictionary for the Firefox spellchecker.
Changed
- Firefox on Windows 11 now uses system provided font icons for the caption buttons, more in line with Windows 11.
Developer
- Firefox will now also clear the back-forward-cache when receiving the Clear-Site-Data: "cache" response header.
Web Platform
- 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.

New
- You can now unload tabs by right-clicking on a tab (or multiple selected tabs) and selecting "Unload Tab". This can be helpful in reducing Firefox's memory and CPU usage.
- Firefox for Android now allows includes a "Select All" in Bookmarks.
- Vertical Tabs: You can now keep more — or fewer — pinned tabs in view. Just drag the divider to resize your pinned tabs section.
- Firefox now supports adding custom search engines. To do so, 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.
- The Firefox Extensions button can now be removed from the toolbar, giving you more control over how you customize 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.
- Firefox builds in Arabic now come with a built-in Arabic dictionary for the Firefox spellchecker.
- You can now lock your private browsing tabs behind your fingerprint or device credentials for added privacy. Enable the setting in Firefox for Android to keep your private tabs secure even when you leave the app.
- Full-Page Translations now prioritize 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.
Changed
- The Pocket toolbar icon, as well as the Pocket integrations on New Tab, have been removed per the service shutdown announcement.
Developer

Web Platform
- 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.
- 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 to style text ranges.
- On all platforms, 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 now supports 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.
- Firefox will now escape less-than (<) and greater-than (>) symbols when serializing HTML attributes, making certain mXSS attacks on websites more difficult.

New
- Full-Page Translations are now available within Firefox extension pages.
Fixed
- PNG images with transparency now keep their transparency when pasted into Firefox.
- The upload performance of HTTP/3 been significantly improved, particularly on resumed connections (QUIC 0-RTT) and high bandwidth and high delay connections.
- Fix for MFSA 2025-36 included in Firefox 139.0b10 and newer.
Developer

Web Platform
- window.getSelection().toString() now correctly returns the text serialization when text is selected in a text control, improving cross-browser interoperability on some sites.
- Closed <details> elements are now searchable and can be automatically expanded if found via find-in-page.
- Timer throttling for Workers is now supported.
- The Temporal proposal is now enabled by default in Firefox. Temporal is a better version of Date, for more details, please see https://spidermonkey.dev/blog/2025/04/11/shipping-temporal.html and https://tc39.es/proposal-temporal/docs/.
- Added support for the WebAuthn largeBlob extension.
- Added support for requestClose() to HTMLDialogElement.
- 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 supports the hidden=until-found attribute, allowing content to be found via find-in-page when it's otherwise hidden by default.
- 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.

New
- Firefox for Android now supports TLS client authentication certificates. When a TLS server requests authentication from the browser, Firefox can now make use of the client certificates that have been added to your Android device.
- Desktop mode in Firefox for Android is now enabled by default on tablets, but can still be disabled from the Site Settings.
- You can now copy links for background tabs using the tabstrip context menu on MacOS and Linux.
- Firefox on Windows 11 now uses acrylic-style menus for popup windows, which better match the operating system’s aesthetic. Users who wish to customize this behavior can do so via the widget.windows.mica.popups preference.
- Firefox for Android now allows you to share a downloaded file or its original URL from the Downloads screen.
Changed
- Rededicated previous color settings to Contrast Control settings. (Learn more)
- 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.
Developer
- Added support for the error.captureStackTrace extension to avoid incompatibility with other browsers. (Learn more)
- We have implemented support for Error.isError, which allows for brand checking whether or not an object is an instance of Error. (Learn more)
- Firefox 138 beta users will have the change where <h1> always has the same UA style, even in <article>, <aside>, <nav>, and <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.
- Added support for the import map integrity field. You can now ensure the integrity of dynamically or statically imported modules.
- A new column was added to the Network panel showing the full path of the request URL. This enhancement makes it easier for developers to quickly view and analyze the complete request paths.
Web Platform
- Applications can now set their preferred degradation method to be utilized when encoding the configured frame rate and resolution cannot be maintained. (Learn more)
- Introduced support for Import Attributes, allowing developers to specify additional metadata when importing modules.
- Firefox now enables the cache directive for the Clear-Site-Data header, allowing websites to clear the networking cache. The header gives websites more control over data stored for their users, such as clearing the network cache during logout, mitigating the risk of privacy leaks. (Learn more)

New
- Firefox now identifies all links in PDFs and turns them into hyperlinks.
- Support HEVC playback on Linux.
- You can now use the Firefox address bar as a calculator. Simply type in arithmetic expression and view the result in the address bar drop-down. Clicking on this result will copy it to your clipboard.
Changed
- Due to recent changes in MacOS Sequoia, the shortcut to complete search strings to .com addresses has been changed on MacOS from Ctrl+Enter to Cmd+Enter. The preference to disable this feature, browser.urlbar.ctrlCanonizesURLs, was not renamed, and it's valid across all the supported platforms.
Developer
- In the Inspector Fonts panel, we now display fonts metadata, like the the font version, designer, vendor, license…

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

Web Platform
- Support for the SVG discard element is now available.
- 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.

New
- On macOS, some background tasks will be moved to lower power cores resulting in less energy use.
- Hardware-accelerated playback of HEVC video content is now supported on macOS.
- Hardware video decoding is now enabled for AMD GPUs on Linux.
- Firefox will upgrade page loads to HTTPS and gracefully fall back to HTTP if that does not succeed. This behavior is known as HTTPS-First.
- Having any issues with a website on Firefox for Android, yet the site seems to be working as expected on another browser? You can now let us know via the Web Compatibility Reporting Tool. To access it:
- Open the Menu via the three-dot button while on a browser tab
- Tap on “Report broken site”
Provide the form with as much information as possible, and you’ll directly help us detect, target, and fix the most impacted sites to make your browsing experience on Firefox smoother.
- Smartblock Embeds allows users to selectively unblock certain social media embeds that are blocked in ETP Strict and Private Browsing modes. Currently, a limited number of embeds are supported with support for more embed types coming in the near future.
Fixed
- Firefox will now prefer PNG when copying images out of Firefox, allowing the preservation of transparency.
Changed
- Cookie Banner Handling by default in Private Browsing is now disabled. This was previously enabled only in Nightly and Beta. The feature can be enabled via the cookiebanners.service.mode and cookiebanners.service.mode.privateBrowsing prefs in about:config.
- macOS DMG packages now use LZMA for compression, reducing download size and installation time.
Developer
- 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.
- 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 CookieStore API, an asynchronous cookie API for scripts running in HTML documents and service workers.
- Firefox now sends a referrer from meta refreshes and Refresh headers.
- Firefox now supports sending multiple simultaneous versions of the same source over WebRTC, so called simulcast, with the H264 video codec. H264 is the second video codec after VP8 to be supported for sending simulcast.
- Firefox now supports sending and receiving the AV1 video codec over WebRTC. Both singlecast and simulcast are supported for sending.
- Added support for ARIA elements reflection.
- Firefox now supports by default the text replacement feature in an input field on macOS. Web content can enable/disable this using the HTML autocorrect attribute.
Also, Firefox for Android hints if the software keyboard supports autocorrect. If supported, the software keyboard suggests autocorrection.

New
- 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.
- Firefox now includes new safeguards to prevent sites from overwhelming the Back history by spamming numerous consecutive visits over a short time.
- To help Mozilla find and fix crashes, you can opt into automatically sharing Firefox for Android crash reports by checking the new Data Collection setting "Automatically submit crash reports".
Changed
- 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. Blog Post
- Some web pages either function as redirects or abuse the history API in order to generate an excessive amount of history entries. Both cases can result in making navigating your browser history via the back/forward buttons annoyingly difficult. This intervention causes these history entries which the user has not interacted with to be skipped by the back and forward buttons.
Developer

Web Platform
- 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.
- Added support for a post-quantum key exchange mechanism (mlkem768x25519) for Http/3.

New
- Firefox now supports touchpad hold gestures on Linux. This means that kinetic (momentum) scrolling can now be interrupted by placing two fingers on the touchpad.
- HEVC hardware support is implemented for Windows users.
Fixed
- Fixed an issue that started with macOS Sonoma where the emoji picker would open and immediately close when opened with the Cmd+Ctrl+Space shortcut.
Thanks to research by Carlos Duarte do Nascimento (Chester) and :bintoro, and a patch by Carlos Duarte do Nascimento (Chester), we have been able to fix this universally for this shortcut and similar shortcuts going forward.
- Fixed an issue that started with macOS Sonoma where the emoji picker would also insert the character "e" in the selected text field/box when opening the emoji picker using the Fn+e shortcut.
We have also fixed this for similar shortcuts using the Fn key.
Changed
- Firefox follows now the model HTML specification for transient user activation more closely. This change makes popup blocking less strict in cases where previous versions of Firefox were overly aggressive, reducing erroneous blocking prompts.
Developer

New
- You can now show tabs from other devices in the Tab overview menu.
- Firefox now supports touchpad hold gestures on Linux. This means that kinetic (momentum) scrolling can now be interrupted by placing two fingers on the touchpad.
- GPU-accelerated Canvas2D is enabled by default on Windows.
- Desktop mode browsing is now enabled by default for large devices on Firefox for Android. This can be controlled via a preference under Settings in "Site settings" previously named "Site permissions".
- When copying text to the clipboard in Private Browsing mode, Firefox for Android now handles it as sensitive content. The toast notification for the clipboard is masked on Android 13 and higher.
- Firefox now has a new anti-tracking feature enabled in Enhanced Tracking Protection "strict" mode: Bounce Tracking Protection. This protection detects bounce trackers based on redirect behavior and periodically purges their cookies and site data to prevent tracking.
Fixed
- If we have the server time, we adjust the "expire" attribute value by adding the delta between the server and the local times. If the current time is set in the future, we consider valid cookies that are not expired for the server.
- Fixed an issue that started with macOS Sonoma where the emoji picker would open and immediately close when opened with the Cmd+Ctrl+Space shortcut.
Thanks to research by Carlos Duarte do Nascimento (Chester) and :bintoro, and a patch by Carlos Duarte do Nascimento (Chester), we have been able to fix this universally for this shortcut and similar shortcuts going forward.
- Fixed an issue that started with macOS Sonoma where the emoji picker would also insert the character "e" in the selected text field/box when opening the emoji picker using the Fn+e shortcut.
We have also fixed this for similar shortcuts using the Fn key.
- The "Picture-in-Picture: auto-open on tab switch" feature from Firefox Labs now behaves more reliably on more sites - auto-opening more videos that you care about, and ignoring ones that you probably don't care about.
Developer

Web Platform
- Firefox now supports the keepalive option in the Fetch API. This feature allows developers to make HTTP requests that can continue to run even after the page is unloaded, such as during page navigation or closing.
- Firefox now supports Permissions API in Worker Context.
- Firefox now dispatches beforetoggle events just before a dialog opens and toggle events after the dialog closes, matching the behavior of popovers.
- Methods are now available on UInt8Array to convert to and from Base64 and hexadecimal encodings. This is an implementation of a Stage 3 TC39 proposal, for more details see the proposal text.
- Added support for image decoding as part of the WebCodecs API. This allows for decoding of images from the main and worker threads.

New
- Firefox now blocks third-party cookie access with Enhanced Tracking Protection's Strict mode.
- WebRender hardware accelerated rendering is now enabled for most SVG Filter Primitives, improving performance of certain graphics-heavy content. Accelerated filters are feBlend, feColorMatrix, feComponentTransfer, feComposite, feDropShadow, feFlood, feGaussianBlur, feMerge and feOffset.
- GPU-accelerated Canvas2D is enabled by default on Windows.
Fixed
- Fix for MFSA 2024-51 is included in Firefox Desktop and DevEdition 132.0b5 builds and newer.
Changed
- As a follow-up to our work to upgrade mixed content starting Firefox 127, we will now also block HTTP-favicons if they can not be received over HTTPS instead.
- Firefox for Android now uses resizes-visual as the default value of the interactive-widget property of the viewport <meta> element. This means that when the software keyboard is shown, Firefox resizes the page's visual viewport but not its layout viewport, avoiding an expensive reflow and resulting in a more usable layout on many pages.
- The "Copy Without Site Tracking" option is now greyed out when no known tracking parameters were found. Please report tracking parameters that aren't removed by filing a bug in Bugzilla.
- The Firefox for Android address bar's default position has moved from the bottom of the screen to the top for new users. You can use the "Customize > Toolbar" setting to move the toolbar back to the bottom.
Developer
- Support for HTTP/2 Push has been removed due to compatibility issues with various sites. This feature is not currently supported by any other major browser.
Web Platform
- The requestVideoFrameCallback() method is now available on the HTMLVideoElement interface. This method enables developers to perform efficient operations on each video frame.
- Added support for a post-quantum key exchange mechanism for TLS 1.3 (mlkem768x25519).
- The getCapabilities method allows applications to gather the media capabilities supported for the live MediaStreamTrack.
- The fetchpriority attribute enables web developers to optimize resource loading by specifying the relative priority of resources to be fetched by the browser. It accepts three values: auto (default priority), low (lower priority), high (higher priority). It can be specified on script, link, img elements, on the RequestInit parameter of the fetch() method and Link response headers. The HTML specification leaves the detailed interpretation of this attribute up to implementers. Firefox will typically use it to increase or decrease the urgency parameter of HTTP/2 and HTTP/3 requests.
Unresolved
- Users may see unexpected changes in button and toolbar layout after receiving the update to 132.0b1. While the cause of this bug was identified and fixed in 132.0b2, the only way to get out of this broken state is to restore customizations back to default and then re-customize. Subsequent changes should then be remembered as expected. We apologize for the inconvenience caused. (Bug 1919721)