Firefox version history

• Better standards support for HTML5, CSS3, MathML, XHR and SMIL
• Better visibility for the Do not track header preference^[203]
• Stability and security improvements^{[204][205][206]}
• Better tuned HTTP idle connection logic^[203]
• Improved canvas, JavaScript, memory, and networking performance
• Improved spell checking for some locales
• Improved desktop environment integration for Linux users
• Better WebGL security (WebGL content can no longer load cross-domain textures).^[207]
• Background tabs have setTimeout and setInterval clamped to 1000 ms to improve performance^[208]
• Gecko version number bumped to 5.0 to match (and from then on stay synced to) Firefox's major version number^[209]
• Added support for CSS animations.
• The Do-Not-Track header preference has been moved to increase discoverability.
• Tuned HTTP idle connection logic for increased performance.
• Improved canvas, JavaScript, memory, and networking performance.
• Improved standards support for HTML5, XHR, MathML, SMIL, and canvas.
• Improved spell checking for some locales.
• Improved desktop environment integration for Linux users.
• WebGL content can no longer load cross-domain textures.
• Background tabs have setTimeout and setInterval clamped to 1000 ms to improve performance.

• Fixed an issue in Mac OS X 10.7 that could cause Firefox to crash^[210]
• Fixed an issue caused by Apple's "Java for Mac OS X 10.6 Update 5" where the Java plugin would not be loaded^[211]

End-of-life 5.0.x product line on August 16, 2011.

• about:permissions, a permissions manager. The user can choose what information can be shared with sites, e.g. location.
• The address bar now highlights the domain of the website you're visiting.
• Streamlined the look of the site identity block.
• Added support for the latest draft version of WebSockets with a prefixed API.
• Added support for EventSource / server-sent events.
• Added support for window.matchMedia.
• Added Scratchpad, an interactive JavaScript prototyping environment.
• Added a new Web Developer menu item and moved development-related items into it.
• Improved usability of the Web Console.
• Improved the discoverability of Firefox Sync.
• Reduced browser startup time when using Panorama.
• Fixed several stability and security issues.

• Revoked the root certificate for DigiNotar due to fraudulent SSL certificate issuance.^[218]

• Removed trust exceptions for certificates issued by Staat der Nederlanden
• Resolved an issue with gov.uk websites.
• Last release for Android 2.0

End-of-life 6.0.x product line on September 27, 2011.

• Drastically improved memory handling for certain use cases.
• Added a new rendering backend to speed up Canvas operations on Windows systems.
• Bookmark and password changes now sync almost instantly when using Firefox Sync.
• The http:// URL prefix is now hidden by default.
• Added support for text-overflow: ellipsis.
• Added support for the Web Timing specification.
• Enhanced support for MathML.
• The WebSocket protocol has been updated from version 7 to version 8.
• Added an opt-in system for users to send performance data back to Mozilla to improve future versions of Firefox.
• Fixed several security and stability issues.
• Last release for Maemo

• Fixed a rare issue where some users could find one or more of their add-ons hidden after a Firefox update.

End-of-life 7.0.x product line on November 8, 2011.

• Removed support for new tab animation due to incompatibilities with some extensions.

• Add-ons installed by third-party programs are now disabled by default.
• Added a one-time add-on selection dialog to manage previously installed add-ons.
• Added Twitter to the search bar.
• Added a preference to load tabs on demand, improving startup time when windows are restored.
• Improved performance and memory handling when using <audio> and <video> elements.
• Added Cross-Origin Resource Sharing (CORS) support for cross-domain textures in WebGL.
• Added support for HTML5 context menus.
• Added support for insertAdjacentHTML().
• Improved CSS hyphen support for many languages.
• Improved WebSocket support.

• Fixed Mac OS X crash that occurred in certain instances when a Java Applet is loaded with Java SE 6 version 1.6.0_29 installed.
• Fixed Windows startup crash caused by RoboForm versions older than 7.6.2.

End-of-life 8.0.x product line on December 20, 2011.

• Added type inference, significantly improving JavaScript performance.
• Improved theme integration for Mac OS X Lion.
• Added two finger swipe navigation for Mac OS X Lion.
• Added support for querying Do Not Track status via JavaScript.
• Added support for the font-stretch CSS property.
• Improved support for the text-overflow CSS property.
• Improved standards support for HTML5, MathML, and CSS.

• Fixed crash on Windows, Mac and Linux

End-of-life 9.0.x product line on January 31, 2012.

• Most add-ons are now compatible with new versions of Firefox by default.
• Anti-Aliasing for WebGL is now implemented.
• CSS3 3D-Transforms are now supported.
• New <bdi> element for bi-directional text isolation, along with supporting CSS properties.
• Full Screen APIs allow you to build a web application that runs full screen.

• Fixed Java applets that sometimes caused text input to become unresponsive.

End-of-life 10.0.x product line on March 13, 2012.

• Security fixes^[251]
• Fixed web workers running out of memory, affecting some add-ons used by organizations.

• Fixed an issue in Firefox ESR 10.0.3 that caused the "Whats New" page to open after an update.
• Fixed extensions.checkCompatibility.* prefs not working in ESR releases.

• Fixed the 10.0.5 Firefox top crash with signature [@ GLEngine@0x620cf ].

• Fixed some text editing inconsistencies.

• Fixed contenteditable breaks in 10.0.7 that middle-click to open links.
• Addressed a fix that allows specifying wildcard that matches all simple netbiosnames in network.automatic-ntlm-auth.trusted-uris.

• Migration of settings from Google Chrome.
• SPDY protocol support (disabled by default).
• RFC 6455 WebSocket protocol support with an unprefixed API.
• Page Inspector Tilt (3D View).
• Sync Add-ons.
• Redesigned HTML5 video controls.
• Style Editor (CSS).

End-of-life 11.0.x product line on April 24, 2012.

• Windows: Firefox is now easier to update with one less prompt (User Account Control).
• Last release for Windows 2000.^[273]
• Reintroduced on-demand loading of pinned tabs after restoring a session.
• Page Source now has line numbers.
• Line breaks are now supported in the title attribute.
• Improvements to "Find in Page" to center search result.
• URLs pasted into the download manager window are now automatically downloaded.
• Support for the text-align-last CSS property has been added.
• Experimental support for ECMAScript 6 Map and Set objects has been implemented.
• Some TinyMCE-based editors failed to load.
• OS X: WebGL performance may be degraded on some hardware.

End-of-life 12.0.x product line on June 5, 2012.

• When opening a new tab, users are now presented with their most visited pages.
• The default home page now has quicker access to bookmarks, history, settings, and more.
• SPDY protocol now enabled by default for faster browsing on supported sites.
• Restored background tabs are not loaded by default for faster startup.
• Smooth scrolling is now enabled by default.
• 72 total improvements to Page Inspector, HTML panel, Style Inspector, Scratchpad and Style Editor.
• The column-fill CSS property has been implemented.
• Experimental support for ECMAScript 6 Map and Set objects has been implemented.
• Support for the CSS3 background-position property extended syntax has been added.
• The :invalid pseudo-class can now be applied to the element.
• The CSS turn angle unit is now supported.

• Fixed an issue when Windows Messenger did not load in Hotmail, and the Hotmail inbox did not auto-update.
• Fixed the Hebrew text that was sometimes rendered incorrectly.
• Fixed an issue in Adobe Flash 11.3 that sometimes caused a crash on quit.

End-of-life 13.0.x product line on July 17, 2012.

Official Firefox Mobile 14.0 release. ^[279][280]

• Google searches now utilize HTTPS.
• Full screen support for Mac OS X Lion implemented.
• Plugins can now be configured to only load on click (about:config).
• The Awesome Bar now auto-completes typed URLs.
• Improved site identity manager, to prevent spoofing of an SSL connection with favicons.
• Pointer Lock API implemented.
• New API to prevent your display from sleeping.
• New text-transform and font-variant CSS improvements for Turkic languages and Greek.
• Long URLs now extend the status bar almost to the whole width of the viewport.
• Gstreamer backend for HTML5 video to allow H.264 playback (needs to be enabled at compile time).

Official Firefox Desktop 14.0 release.^[281]

• Fixed the GIF animation that can get stuck when src and image size are changed.
• Mac OS X: Fixed the nsCocoaWindow::ConstrainPosition that uses wrong screen in multi-display setup.
• Fixed the CSS :hover regression when an element's class name is set by JavaScript.

End-of-life 14.0.x product line on August 28, 2012.

• Silent update: Background updates.
• Support for SPDY networking protocol v3.
• WebGL enhancements, including compressed textures for better performance.
• Localization in Maithili.
• Optimized memory usage for add-ons.
• JavaScript debugger integrated into developer tools.
• New layout view added to Inspector.
• High precision event timer implemented.
• The CSS word-break property has been implemented.
• New responsive design tool allows web developers to switch between desktop and mobile views of sites.
• Native support for the Opus audio format added.
• The <audio> and <video> elements now support the played attribute.
• The source element now supports the media attribute.
• Fixed the focus rings that keep growing when repeatedly tabbing through elements.

• Addressed a fix where sites visited while in Private Browsing mode could be found through manual browser cache inspection.

End-of-life 15.0.x product line on October 9, 2012.

• Firefox on Mac OS X now has preliminary VoiceOver support turned on by default.
• Initial web app support (Windows/Mac/Linux).
• Acholi and Kazakh localizations added.
• Improvements around JavaScript responsiveness through incremental garbage collection.
• New Developer Toolbar with buttons for quick access to tools, error count for the Web Console, and a new command line for quick keyboard access.
• CSS3 Animations, Transitions, Transforms and Gradients unprefixed.
• Recently opened files list in Scratchpad implemented.
• Fixed an issue where debugger breakpoints do not catch on page reload.
• No longer supporting MD5 as a hash algorithm in digital signatures.
• Opus support by default.
• Reverse animation direction has been implemented.
• Per tab reporting in about:memory.
• User Agent strings for pre-release Firefox versions now show only major version.

• Last release for Mac OS X Leopard (Intel)

End-of-life 16.0.x product line on November 20, 2012.

• First revision of the Social API and support for Facebook Messenger.
• Click-to-play blocklisting implemented to prevent vulnerable plugin versions from running without the user's permission.
• Updated Awesome Bar experience with larger icons.
• Mac OS X 10.5 is no longer supported.
• JavaScript Maps and Sets are now iterable.
• SVG FillPaint and StrokePaint implemented.
• Improvements that make the Web Console, Debugger and Developer Toolbar faster and easier to use.
• New Markup panel in the Page Inspector allows easy editing of the DOM.
• Sandbox attribute for iframes implemented, enabling increased security.
• Over twenty performance improvements, including fixes around the New Tab page.
• Fixed pointer lock that doesn't work in web apps.
• Fixed page scrolling on sites with fixed headers.

• Reverted user agent change causing some website incompatibilities.
• Fixed font rendering issue.

End-of-life 17.0.x product line on January 8, 2013.

• Fixed improvements to the Click-to-Play vulnerable plugin blocklisting feature.^[292]

• Updated ESR17 to NSS 3.14.5 RTM.

End-of-life 17.0.x ESR product line on December 10, 2013.

• Adds a Metro user interface on Windows 8.

• Faster JavaScript performance via IonMonkey compiler.
• Support for Retina displays on OS X 10.7 and up.
• Preliminary support for WebRTC.
• Better image quality with Mozilla's new HTML scaling algorithm.
• Performance improvements around tab switching.
• Support for new DOM property window.devicePixelRatio.
• Improvement in startup time through smart handling of signed extension certificates.
• Support for W3C touch events implemented, taking the place of MozTouch events.
• Disable insecure content loading on HTTPS pages.
• Improved responsiveness for users on proxies.

• Fixed problems involving HTTP Proxy Transactions.
• Fixed unity player crashes on Mac OS X.
• Disabled HIDPI support on external monitors to avoid rendering glitches.

• Built-in PDF Viewer.
• Canvas elements can export their content as an image blob using canvas.toBlob().
• Startup performance improvements.
• Debugger now supports pausing on exceptions and hiding non-enumerable properties.
• Remote Web Console is available for connecting to Firefox on Android or Firefox OS (experimental, set devtools.debugger.remote-enabled to true).
• There is now a Browser Debugger available for add-on and browser developers (experimental, set devtools.chrome.enabled to true).
• Web Console CSS links now open in the Style Editor.
• CSS @page is now supported.
• CSS viewport-percentage length units implemented (vh, vw, vmin and vmax).
• CSS text-transform now supports full-width.
• Fixed certain valid WebGL drawing operations that were incorrectly rejected, leaving incomplete rendering in affected pages.
• Fixed an issue that starting Firefox with -private flag incorrectly claims you are not in Private Browsing mode.
• Fixed plugins that stop rendering when the top half of the plugin is scrolled off the top of the page, in HiDPI mode.

• Windows 8 only: Fixed stability issue for some AMD Radeon HD graphics cards.

• Last release for Android 2.1

End-of-life 19.0.x product line on April 2, 2013.

• Per-window Private Browsing.
• New download experience.
• Ability to close hanging plugins, without the browser hanging.
• Continued performance improvements around common browser tasks (page loads, downloads, shutdown, etc.).
• Continued implementation of draft ECMAScript 6 – clear() and Math.imul.
• New JavaScript Profiler tool.
• getUserMedia implemented for web access to the user's camera and microphone (with user permission).
• <canvas> now supports blend modes.
• Various <audio> and <video> improvements.
• Fixed: Details button on Crash Reporter.
• Fixed: Unity plugin that doesn't display in HiDPI mode.

• Windows-only update to handle issues around handling UNC paths.

End-of-life 20.0.x product line on May 14, 2013

• The Social API now supports multiple providers.
• Enhanced three-state UI for Do Not Track (DNT).
• Preliminary implementation of Firefox Health Report.
• Firefox will suggest how to improve your application startup time if needed.
• Ability to Restore removed thumbnails on New tab Page.
• CSS -moz-user-select:none selection changed to improve compatibility with -webkit-user-select:none.
• Graphics related performance improvements.
• Removed E4X support from SpiderMonkey.
• Implemented Remote Profiling.
• Integrated, Add-on SDK loader and API libraries into Firefox.
• Added support for <main> element.
• Implemented scoped stylesheets.
• Fixed: Some function keys may not work when pressed.
• Fixed: Browsing and Download history clearing needs unification to avoid confusion on clearing download history.

End-of-life 21.0.x product line on June 25, 2013.

• WebRTC is now enabled by default.
• Windows: Firefox now follows display scaling options to render text larger on high-res displays.
• Mac OS X: Download progress in Dock application icon.
• HTML5 audio/video playback rate can now be changed.
• Social services management implemented in Add-ons Manager.
• asm.js optimizations (OdinMonkey) enabled for major performance improvements.
• Improved WebGL rendering performance through asynchronous canvas updates.
• Plain text files displayed within Firefox will now word-wrap.
• For user security, the |Components| object is no longer accessible from web content.
• Improved memory usage and display time when rendering images.
• Pointer Lock API can now be used outside of fullscreen.
• CSS3 Flexbox implemented and enabled by default.
• New Web Notifications API implemented.
• Added clipboardData API for JavaScript access to a user's clipboard.
• New built-in font inspector.
• New HTML5 <data> and <time> elements
• Fixed: Scrolling using some high-resolution-scroll aware touchpads feels slow.

End-of-life 22.0.x product line on August 6, 2013.

In this Version Mozilla changed the Firefox Logo.

• Mixed content blocking enabled to protects users from man-in-the-middle attacks and eavesdroppers on HTTPS pages.
• Options panel created for Web Developer Toolbox.
• "Enable JavaScript" preference checkbox has been removed and user-set values will be reset to the default.
• Improved about:memory's functional UI.
• Simplified interface for notifications of plugin installation.
• Enabled DXVA2 on Windows Vista+ to accelerate H.264 video decoding.
• Users can now switch to a new search provider across the entire browser.
• CSP policies using the standard syntax and semantics will now be enforced.
• <input type='file'> rendering improvements.
• Replaced fixed-ratio audio resampler in webrtc.org capture code with Speex resampler and eliminated pseudo-44,000 Hz rate.
• "Load images automatically" and "Always show the tab bar" checkboxes removed from preferences and reset to defaults.
• HTML5 <input type="range"> form control implemented.
• Write more accessible pages on touch interfaces with new ARIA role for key buttons.
• Social share functionality.
• Added unprefixed requestAnimationFrame.
• Implemented a global browser console.
• Dropped blink effect from text-decoration: blink; and completely removed <blink> element.
• New feature in toolbox: Network Monitor.

• Fixed rendering glitches on H.264 video only in FF23 on Vista.
• Fixed spellchecking that was broken with non-ASCII characters in profile path.
• Fixed audio static/"burble"/breakup in Firefox to Firefox WebRTC calls.

End-of-life 23.0.x product line on September 17, 2013.

• Support for new scrollbar style in Mac OS X 10.7 and newer.
• Implemented Close tabs to the right.
• Social: Ability to tear-off chat windows to view separately by simply dragging them out.
• Accessibility related improvements on using pinned tabs.
• Removed support for Revocation Lists feature.
• Performance improvements on New Tab Page loads.
• Major SVG rendering improvements around Image tiling and scaling.
• Improved and unified Browser console for enhanced debugging experience, replacing existing Error console.
• Removed support for sherlock files that are loaded from application or profile directory.
• Replaced fixed-ratio audio resampler in webrtc.org capture code with Speex resampler and eliminated pseudo-44,000  rate.

End-of-life 24.0.x product line on October 29, 2013.

• Updated branches that use 4.10 RTM to 4.10.2 RTM.
• Updated Mozilla to NSS 3.15.3 (new alternative NSS branch) to pick up a few fixes.
• Fixed an issue where some UI strings in Firefox 24.1.0 ESR l10n builds are in English.

• Web Audio support.
• The find bar is no longer shared between tabs.
• If away from Firefox for months, you now will be offered the option to migrate another browser's history and settings.
• Resetting Firefox no longer clears your browsing session.
• CSS3 background-attachment:local support to control background scrolling.
• Many new ES6 functions implemented.
• iframe document content can now be specified inline.
• Fixed blank or missing page thumbnails when opening a new tab.

• Fixed pages that sometimes wouldn't load without first moving the cursor.

End-of-life 25.0.x product line on December 10, 2013

• All Java plug-ins are defaulted to 'click to play'.
• Password manager now supports script-generated password fields.
• Updates can now be performed by Windows users without write permissions to Firefox install directory (requires Mozilla Maintenance Service).
• Support for H.264 on Linux if the appropriate gstreamer plug-ins are installed.
• Support for MP3 decoding on Windows XP, completing MP3 support across Windows OS versions.
• CSP implementation now supports multiple policies, including the case of both an enforced and Report-Only policy, per the specification.
• Social API now supports Social Bookmarking for multiple providers through its SocialMarks functionality.
• Math.ToFloat32 takes a JavaScript value and converts it to a Float32, whenever possible.
• There is no longer a prompt when websites use appcache.
• Support for the CSS image orientation property.
• New App Manager allows you to deploy and debug HTML5 webapps on Firefox OS phones and the Firefox OS Simulator.
• IndexedDB can now be used as a "optimistic" storage area so it doesn't require any prompts and data is stored in a pool with LRU eviction policy, in short temporary storage.
• Fixed: When displaying a standalone image, Firefox matches the Exif orientation information contained within the JPEG image.
• Fixed: Text Rendering Issues on Windows 7 with Platform Update KB2670838 (MSIE 10 Prerequisite) or on Windows 8.1.
• Improved page load times due to no longer decoding images that are not visible.
• Fixed: AudioToolbox MP3 backend for Mac OS X.

• Fixed the screen that distorts on some devices after tapping on search suggestion.
• Fixed: About:home is missing translations in some locales. Most affected are: ca, ga-IE, hu, ko, pt-BR, pt-PT, ro, and uk.
• Fixed: In some cases, the clip set on the page doesn't update when the addressbar hides.
• Fixed: Invalid position:fixed rendering.

End-of-life 26.0.x product line on February 4, 2014.

• You can now run more than one service at a time with Firefox SocialAPI, allowing you to receive notifications, chat and more from multiple integrated services.
• Enabled TLS 1.1 (RFC 4346) and TLS 1.2 (RFC 5246) by default.
• Added support for SPDY 3.1 protocol.
• Ability to reset style sheets using all:unset.
• You can now choose to deobfuscate javascript in the debugger.
• Added support for scrolled fieldsets.
• Implemented allow-popups directive for iframe sandbox, enabling increased security.
• CSS cursor keywords -moz-grab and -moz-grabbing have been unprefixed.
• Added support for ES6 generators in SpiderMonkey.
• Implemented support for mathematical function Math.hypot() in ES6.
• Dashed line support on Canvas.
• Had Azure/Skia content rendering working on Linux.

• Fixed stability issues with Greasemonkey and other JavaScript that used ClearTimeoutOrInterval.
• Fixed: JavaScript math correctness issue.

End-of-life 27.0.x product line on March 18, 2014.

• VP9 video decoding implemented.
• Mac OS X: Notification Center support for web notifications.
• Volume control for HTML5 audio/video.
• Support for Opus in WebM.
• Now that SPDY/3 is implemented support for SPDY/2 has been removed and servers without SPDY/3 will negotiate to HTTP/1 without any penalty.
• Support for MathML 2.0 'mathvariant' attribute.
• Background thread hang reporting.
• Support for multi-line flexbox in layout.

Off-cycle stability mobile update.^[352]

• Fixed: No H.264 video playback on several Galaxy devices.
• Fixed: Mobile-only security fix for file:paths.

End-of-life 28.0.x product line on April 29, 2014.

• Significant new customization mode.
• A new menu sits in the right hand corner of Firefox and includes popular browser controls.
• New tabs provide an overall smoother look and fade into the background when not active.
• An interactive onboarding tour to guide users through the new Firefox changes.
• Added the ability to set up Firefox Sync by creating a Firefox account.
• Gamepad API finalized and enabled.
• Malay [ma] locale added.
• Clicking on a W3C Web Notification will switch to the originating tab.
• 'box-sizing' (dropping the -moz- prefix) implemented.
• Console object available in web workers.
• Promises enabled by default.
• SharedWorker enabled by default.
• <input type="number"> implemented and enabled.
• <input type="color"> implemented and enabled.
• Enabled ECMAScript Internationalization API.
• Add-on bar has been removed, content moved to navigation bar.
• No longer possible to move tabs from the top of the browser without an add-on.

• Fixed: An issue with pdf.js printing white pages.
• Fixed: Tabs not visible with dark themes under Windows 8.1.
• Fixed: Session Restore failed with a corrupted sessionstore.js file.
• Fixed: Seer disabled by default.

End-of-life 29.0.x product line on June 10, 2014.

• Sidebars button in browser chrome enables faster access to social, bookmark, & history sidebars.
• Mac OS X command-E sets find term to selected text.
• Support for GStreamer 1.0.
• Disallowed calling WebIDL constructors as functions on the web.
• With the exception of those bundled inside an extension or ones that are whitelisted, plugins will no longer be activated by default.
• Fixes to box-shadow and other visual overflow.
• Mute and volume available per window when using WebAudio.
• Background-blend-mode enabled by default.
• Use of line-height allowed for <input type="reset|button|submit">.
• ES6 array and generator comprehensions implemented.
• Error stack now contains column number.
• Support for alpha option in canvas context options.
• Fixed: Ignored autocomplete="off" when offering to save passwords via the password manager.
• Fixed TypedArrays that don't support new named properties.

End-of-life 30.0.x product line on July 22, 2014.

• Adds the search field to the new tab page.
• mozilla::pkix as default certificate verifier.
• Blocks malware from downloaded files.
• Partial implementation of the OpenType MATH table.
• Support of Prefer:Safe http header for parental control.
• audio/video .ogg and .pdf files handled by Firefox if no application specified (Windows only).
• Upper Sorbian [hsb] locale added.
• Removal of the CAPS infrastructure for specifying site-specific permissions (via capability.policy.* preferences). Most notably, attempts to use this functionality to grant access to the clipboard will no longer work. The sole exception is the checkloaduri permission, which may still be used as before to allow sites to load file:// URIs.
• WebVTT implemented and enabled.
• CSS3 variables implemented.
• Developer Tools: Add-on Debugger.
• Developer Tools: Canvas Debugger.
• New Array built-in: Array.prototype.fill().
• New Object built-in: Object.setPrototypeOf().
• CSP 1.1 nonce-source and hash-source enabled by default.
• Developer Tools: Eyedropper tool added to the color picker.
• Developer Tools: Editable Box Model.
• Developer Tools: Code Editor improvements.
• Developer Tools: Console stack traces.
• Developer Tools: Copy as cURL.
• Developer Tools: Styled console logs.
• navigator.sendBeacon enabled by default.
• Dialogs spawned from the onbeforeunload event no longer block access to the rest of the browser.
• Fixed: Search for partially selected link text from context menu.
• Last release for ARMv7 Android 2.2

End-of-life 31.0.x product line on September 2, 2014.

• Fixed: Invalid certificate issue with mozilla::pkix.
• Fixed: Importing an RSA private key fails if p < q.

• Fixed: @ JS::Handle::operator JSObject* const&() startup crash.
• Fixed: Intermittent failures in add-ons manager mochitest-browser tests.
• Fixed: Bad CPU type in executable running mochitests on Mac OS X Yosemite.
• Fixed: Error building nsChildView.mm on Mac OS X Yosemite.
• Fixed: Build error on Mac OS X Yosemite.
• Fixed: Wrong CPU features detection on some x86 CPUs.
• Fixed: XMLHttpRequest.send({}) should not throw.
• Last release for ARMv6 Android

• New HTTP cache provides improved performance including crash recovery.
• Integration of generational garbage collection.
• Public key pinning support enabled.
• Displays the number of found items in the find toolbar.
• Easier back, forward, reload, and bookmarking through the context menu.
• Views historical use information for logins stored in password manager.
• Lower Sorbian [dsb] locale added.
• Removed and turned off trust bit for some 1024-bit root certificates.
• Performance improvements to Password Manager and Add-on Manager.
• drawFocusIfNeeded enabled by default.
• CSS position:sticky enabled by default.
• mix-blend-mode enabled by default.
• Vibration API updated to latest W3C spec.
• box-decoration-break enabled by default.
• ECMAScript 6 built-in method Array#copyWithin implemented.
• New Array built-in: Array.from()
• navigator.languages property and languagechange event implemented.
• CSS box-decoration-break replaces -moz-background-inline-policy.
• HiDPI support in Developer Tools UI.
• Inspector button moved to the top left.
• Hidden nodes displayed differently in the markup-view.
• New Web Audio Editor.
• Code completion and inline documentation added to Scratchpad.
• Fixed: Mac OS X: cmd-L does not open a new window when no window is available.
• Fixed Text Rendering Issues on Windows 7 with Platform Update KB2670838 (MSIE 10 Prerequisite) or on Windows 8.1.

Desktop

• Fixed stability issues for computers with multiple graphics cards.
• Fixed mixed content icon that may be incorrectly displayed instead of lock icon for SSL sites.
• Fixed: WebRTC: setRemoteDescription() silently fails if no success callback is specified.

Android

• Fixed link tap selection that was offset on some Android devices.

Off-cycle stability update.^[370]

• Fixed corrupt installations causing Firefox to crash on update.

• Windows: OMTC enabled by default.
• OpenH264 support (sandboxed).
• Improved search experience through the location bar.
• Slimmer and faster JavaScript strings.
• Search suggestions on the Firefox Start (about:home) and new tab (about:newtab) pages.
• New CSP (Content Security Policy) backend.
• Support for connecting to HTTP proxy over HTTPS.
• Improved reliability of the session restoration.
• Azerbaijani [az] locale added.
• Proprietary window.crypto properties/functions removed.
• JSD (JavaScript Debugger Service) removed in favor of the Debugger interface.
• @counter-style rule from CSS3 Counter Styles specification implemented.
• DOMMatrix interface implemented.
• Cubic-bezier curves editor.
• Displayed which elements have listeners attached.
• New sidebar which displays a list of shortcuts to every @media rule in the current stylesheet.
• Paint flashing for browser content repaints.
• Editable @keyframes rules in the Rules section of the Inspector.
• CSS transform highlighter in the style-inspector.
• Fixed incomplete downloads being marked as complete by detecting broken HTTP1.1 transfers.

Off-cycle stability update.^[374]

• Fixed: Firefox displays a black screen at startup with certain graphics drivers.

Off-cycle stability update.^[375]

• Fixed a startup crash with some combination of hardware and drivers.

Off-cycle stability update.^[376]

• Blacklisted graphics drivers that were causing black screens with OMTC enabled.
• Fixed two startup crashes with some combination of hardware and drivers.

• Forget button added.
• Enhanced tiles.
• Privacy tour introduced.
• Adding DuckDuckGo as a search option.

Off-cycle stability update.^[379]

• Fixed a startup crash.

End-of-life 33.x product line on December 1, 2014.

• Default search engine changed to Yandex for Belarusian, Kazakh, and Russian locales.
• Improved search bar (en-US only).
• Firefox Hello real-time communication client.
• Easily switch themes/personas directly in the Customizing mode.
• Wikipedia search now uses HTTPS for secure searching (en-US only).
• Implementation of HTTP/2 (draft14) and ALPN.
• Recover from a locked Firefox process in the "Firefox is already running" dialog on Windows.
• Disabled SSLv3.
• Proprietary window.crypto properties/functions re-enabled (to be removed in Firefox 35).
• Firefox signed by Apple OS X version 2 signature.
• ECMAScript 6 WeakSet Implemented.
• JavaScript Template Strings Implemented.
• CSS3 Font variants and features control (e.g. kerning) implemented.
• WebCrypto:
  • RSA-OAEP, PBKDF2, ECDH, and AES-KW support.
  • wrapKey and unwrapKey implemented.
  • Import/export of JWK-formatted keys.
• matches() DOM API implemented (formerly mozMatchesSelector()).
• Performance.now() for workers implemented.
• WebIDE: Create, edit, and test a new Web application from your browser.
• Highlight all nodes that match a given selector in the Style Editor and the Inspector's Rules panel.
• Improved User Interface of the Profiler.
• console.table function added to web console.
• Fixed: CSS transitions start correctly when started at the same time as changes to display, position, overflow, and similar properties.

Official Firefox 34.0.5 release.

• Default search engine changed to Yahoo! for North America.

End-of-life 34.0.x product line on January 13, 2015.

Renamed to Firefox Developer Edition since November 10, 2014.^[381][382]

• Firefox Hello with new rooms-based conversations model.
• New search UI improved and enabled for more locales.
• Access the Firefox Marketplace from the Tools menu and optional toolbar button.
• Built-in support for H264 (MP4) on Mac OS X Snow Leopard (10.6) and newer through native APIs.
• Use of tiled rendering on Mac OS X.
• Improved high quality image resizing performance.
• Improved handling of dynamic styling changes to increase responsiveness.
• Implemented HTTP Public Key Pinning Extension (for enhanced authentication of encrypted connections).
• Added support for the CSS Font Loading API.
• Resource Timing API implemented.
• CSS filters enabled by default.
• Changed JavaScript 'let' semantics to match the ES6 specification.
• Support for inspecting ::before and ::after pseudo elements.
• Computed view: Nodes matching the hovered selector are now highlighted.
• Network Monitor: New request/response headers view.
• Added support for the EXT_blend_minmax WebGL extension.
• Fixed: Show DOM Properties context menu item in inspector.
• Reduced resource usage for scaled images.
• PDF.js updated to version 1.0.907.
• Non-HTTP(S) XHR now returns correct status code.

• Fixed a crash with the Enhanced Steam extension.
• Fixed a potential startup crash.
• Fixed Kerberos authentication failure with alias.
• Fixed SVG / CSS animation regression causing rendering issues on websites like openstreetmap.org.
• Fixed a crash on Godaddy webmail.
• Fixed an update failure of document.baseURI to document.location after base tag was removed from DOM for site with a CSP.
• Fixed a text selection broken with a Right-to-left (RTL) version of Firefox.
• CSP had a change in behavior with regard to case sensitivity resources loading.

Android

• Fixed crash with video playback on Asus MeMO Pad 10 and 8, Tesco Hudl, Lenovo Lifetab E models, and several other devices running the Rockchip SoC.

End-of-life 35.0.x product line on February 24, 2015.

• Pinned tiles on the new tab page can be synced.
• Added full support for HTTP/2.
• Locale added: Uzbek (UZ).
• Remote option removed.
• No longer accepting insecure RC4 ciphers whenever possible.
• Phasing out Certificates with 1024-bit RSA Keys.
• Shut down hangs will now show the crash reporter before exiting the program.
• Add-on compatibility changed.
• Support for the ECMAScript 6 Symbol data type added.
• Unicode-range CSS descriptor implemented.
• CSSOM-View scroll behavior implemented allowing smooth scrolling of content without custom libraries.
• Object-fit and object-position implemented.
• Isolation CSS property implemented.
• CSS3 will-change property implemented.
• Changed JavaScript 'const' semantics to conform better to the ES6 specification.
• Improved ES6 generators for better performance.
• Eval sources now appear in the Debugger.
• DOM Promises inspection.
• Inspector: More paste options in markup view.
• CSS gradients work on premultiplied colors.
• Fixed some unexpected logout from Facebook or Google after restart.

• Disabled the usage of the ANY DNS query type.
• Fixed a startup crash with EMET.
• Fixed the Hello contact that may become inactive until restart.
• Fixed print preferences that may not be preserved.
• Fixed Hello contact tabs that may not be visible.
• Accepted hostnames that include an underscore character _.
• Fixed the WebGL that may use significant memory with Canvas2d.
• Option -remote has been restored.
• Fixed a top crash.

Off-cycle stability mobile update.^[388]

• Fixed a startup crash on HTC One M8 devices (Verizon) with Android 5.0.1.
• Fixed some potential crashes with Flash videos.

• Security fix for an issue disclosed at HP Zero Day Initiative's Pwn2Own contest.

• Security fix for an issue disclosed at HP Zero Day Initiative's Pwn2Own contest.

End-of-life 36.0.x product line on March 31, 2015.

• Heartbeat user rating system – your feedback about Firefox.
• Yandex set as default search provider for the Turkish locale.
• Bing search now uses HTTPS for secure searching.
• Improved protection against site impersonation via OneCRL centralized certificate revocation.
• Opportunistically encrypts HTTP traffic where the server supports HTTP/2 AltSvc.
• Disabled insecure TLS version fallback for site security.
• Extended SSL error reporting for reporting non-certificate errors.
• TLS False Start optimization now requires a cipher suite using AEAD construction.
• Improved certificate and TLS communication security by removing support for DSA.
• Improved performance of WebGL rendering on Windows.
• Implemented a subset of the Media Source Extensions (MSE) API to allow native HTML5 playback on YouTube.
• Added support for CSS display:contents.
• IndexedDB now accessible from worker threads.
• New SDP/JSEP implementation in WebRTC.
• Debug tabs opened in Chrome Desktop, Chrome for Android, and Safari for iOS.
• New Inspector animations panel to control element animations.
• New Security Panel included in Network Panel.
• Debugger panel support for chrome:// and about:// URIs.
• Added logging of weak ciphers to the web console.

• Disabled HTTP/2 AltSvc.

Desktop

• Fixed start-up crash due to graphics hardware and third party software.

Android

• Fixed crash due to WebRTC usage on certain web sites.

Desktop

• Fixed an issue with Google Maps rendering incorrectly in some cases.
• Fixed stability issues for some graphics hardware and feature sets.
• Security fixes.

Android

• Fixed an issue related to the "request desktop site" feature.

End-of-life 37.0.x product line on May 12, 2015.

• New tab-based preferences.
• Ruby annotation support.
• Base for the next ESR release.
• autocomplete=off is no longer supported for username/password fields.
• URL parser avoids doing percent encoding when setting the Fragment part of the URL, and percent decoding when getting the Fragment in line with the URL spec.
• RegExp.prototype.source now returns "(?:)" instead of the empty string for empty regular expressions.
• Improved page load times via speculative connection warmup.
• WebSocket now available in web workers.
• BroadcastChannel API implemented.
• Implemented srcset attribute and <picture> element for responsive images.
• Implemented DOM3 Events KeyboardEvent.code.
• Mac OS X: Implemented a subset of the Media Source Extensions (MSE) API to allow native HTML5 playback on YouTube.
• Implemented Encrypted Media Extensions (EME) API to support encrypted HTML5 video/audio playback (Windows Vista or later only).
• Automatically downloaded Adobe Primetime Content Decryption Module (CDM) for DRM playback through EME (Windows Vista or later only).
• Optimized-out variables are now visible in Debugger UI.
• XMLHttpRequest logs in the web console are now visually labelled and can be filtered separately from regular network requests.
• WebRTC now has multistream and renegotiation support.
• copy command added to console.

Desktop

• Fixed a crash on start-up with first generation NVidia Optimus graphics cards.
• Fixed a problem in which users who import cookies from Google Chrome can end up with broken websites.
• Fixed a problem that large animated images may fail to play and may stop other images from loading.
• Fixed a problem that WebRTC H264 video streams from CiscoSpark native clients are not decoded correctly (Fixed in Firefox ESR 38.0.1; was already fixed in Firefox 38.0).

Android

• Fixed a crash on start-up on devices for which Firefox does not support Android hardware acceleration.
• Fixed a problem that large animated images may fail to play and may stop other images from loading.
• Fixed a problem that Mozilla Location Service (MLS) stumbler may not submit all data.

Desktop

• Integration of Pocket.
• Implementation of Reader View.
• Share the active tab or window in a Hello conversation.
• Fixed a problem that would cause Firefox to stop painting when switching tabs.
• Fixed graphics performance when using the built-in VGA driver on Windows 7.

Android

• Integrated Adjust SDK to measure aggregate installs.
• Fixed various stability fixes.

End-of-life 38.0.x product line on July 2, 2015.

• Patches zero-day exploit.^[398]

• Fixed: Firefox may become unresponsive after right-clicking Flash content on Windows 8.
• Fixed: Firefox may crash during mp4 video playback.
• Fixed branded Firefox application that does not open URLs in system default browser.
• Fixed significant memory leak with GreaseMonkey add-on.
• Fixed crash [@ RtlEnterCriticalSection | MessageLoop::PostTask_Helper] on browser shutdown.
• Fixed browser UI that becomes unresponsive state when using Unity Web Player Plugin.
• Fixed ESRs that would not build on hppa platform.
• Fixed crash in mozilla::layers::SyncObjectD3D11::FinalizeFrame().

• Improved stability with Java.

• Preparing to use SHA-256 signing certificate for Windows builds, to meet new signing requirement.

• Use of a SHA-256 signing certificate for Windows builds, to meet new signing requirements.

• Updated graphite2 library to latest release.

• Fixed an issue in which loading from history can show the wrong url in the location bar.
• Disabled Graphite font shaping library.

• Share Hello URLs with social networks.
• Project Silk for Mac OS X: Smoother animation and scrolling.
• Support for 'switch' role in ARIA 1.1 (web accessibility).
• SafeBrowsing malware detection lookups enabled for downloads on Mac OS X and Linux.
• Support for new Unicode 8.0 skin tone emoji.
• Removed support for insecure SSLv3 for network communications.
• Disable use of RC4 except for temporarily whitelisted hosts.
• The malware detection service for downloads now covers common Mac file types.
• Performance of displaying dashed lines is improved on Mac OS X.
• List-style-type now accepts a string value.
• Enable the Fetch API for network requests from dedicated, shared and service workers.
• Cascading of CSS transitions and animations now matches the current spec.
• Implement <link rel="preconnect">allowing anticipation of a future connection without revealing any information.
• Added support for CSS Scroll Snap Points.
• Drag and drop enabled for nodes in Inspector markup view.
• Webconsole input history persists even after closing the toolbox.
• Cubic bezier tooltip now shows a gallery of timing-function presets for use with CSS animations.
• localhost is now available offline for WebSocket connections.
• Improve performance for IPv6 fallback to IPv4.
• Fixed incomplete downloads being marked as complete by detecting broken HTTP1.1 transfers.
• Fixed the security state indicator on a page now correctly ignores loads caused by previous pages.
• Fixed an issue where a Hello conversation window would sometimes fail to open.
• Fixed a regression that could lead to Flash not displaying has been fixed.
• Update to NSS 3.19.2.

• Patches zero-day exploit.^[398]

End-of-life 39.0.x product line on August 11, 2015.

• Support for Windows 10.
• Added protection against unwanted software downloads.
• User can receive suggested tiles in the new tab page based on categories Firefox matches to browsing history (en-US only).
• Hello allows adding a link to conversations to provide context on what the conversation will be about.
• New style for add-on manager based on the in-content preferences style.
• Improved scrolling, graphics, and video playback performance with off-main-thread compositing (Linux only).
• Graphic blocklist mechanism improved: Firefox version ranges can be specified, limiting the number of devices blocked.
• Add-on extensions that are not signed by Mozilla will display a warning.
• NPAPI Plug-in performance improved via asynchronous initialization.
• Smoother animation and scrolling with hardware vsync (Windows only).
• JPEG images use less memory when scaled and can be painted faster.
• Sub-resources can no longer request HTTP authentication, thus protecting users from inadvertently disclosing login data.
• IndexedDB transactions are now non-durable by default.
• Implemented AudioBufferSourceNode.detune to modulate playback rate in cents, a logarithmic unit of measure used for musical intervals.
• Improved Performance tools in the developer tools: Waterfall view, Call Tree view and a Flame Chart view.
• New rules view tooltip in the Inspector to tweak CSS Filter values.
• Console API messages from SharedWorker and ServiceWorker are now displayed in web console.
• New page ruler highlighting tool that displays lightweight horizontal and vertical rules on a page.
• Inspector now searches across all content frames in a page.
• Fixed Kannada text that does not display properly in built-in pdf viewer.

• Enabled API allowing Windows 10 users to open settings dialog.
• Fixed mozalloc.lib that was missing from the xulrunner package.
• Fixed a startup crash with some combination of hardware and drivers.

• Disabled the asynchronous plugin initialization.
• Fixed a segmentation fault in the GStreamer support (Linux only).
• Fixed a startup crash when using DisplayLink (Windows only).
• Fixed a regression with some Japanese fonts used in the <input> field.
• Fixed an issue that the selection in a select combox box using the mouse could be broken on some sites.
• Fixed an issue that some search partner codes were missing.

End-of-life 40.0.x product line on September 22, 2015.

• Enhanced IME support on Windows (Vista +) using TSF (Text Services Framework).
• Ability to set a profile picture for your Firefox Account.
• Firefox Hello now includes instant messaging.
• SVG images can be used as favicons.
• Improved box-shadow rendering performance.
• WebRTC now requires perfect forward secrecy.
• WARP is disabled on Windows 7.
• Updates to image decoding process.
• Support for running animations of 'transform' and 'opacity' on the compositor thread.
• MessageChannel and MessagePort API enabled by default.
• Added support for the transform-origin property on SVG elements.
• CSS Font Loading API enabled by default.
• Navigator.onLine now varies with actual internet connectivity (Windows and Mac OS X only).
• Copy/Cut Web content from JavaScript to the OS clipboard with document.execCommand("cut"/"copy").
• Implemented Cache API for querying named caches that are accessible Window, Worker, and ServiceWorker.
• Removed support for binary XPCOM components in extensions, use addon SDK "system/child_process" pipe mechanism for native binaries instead.
• Network requests can be exported in HAR format.
• Quickly adds new CSS rule with New Rule button in the Inspector.
• Screenshots a node or element from markup view with the Screenshot Node context menu item.
• Copies element CSS rule declarations with the Copy Rule Declaration context menu item in the Inspector.
• Pseudo-Class panel in the Inspector.
• Fixed an issue where picture element does not react to resize/viewport changes.

Off-cycle stability update.^[417]

• Fixed a startup crash related to Yandex toolbar and Adblock Plus.
• Fixed potential hangs with Flash plugins.
• Fixed a regression in the bookmark creation.
• Fixed a startup crash with some Intel Media Accelerator 3150 graphic cards.
• Fixed a graphic crash, occurring occasionally on Facebook.

• Private Browsing with Tracking Protection that blocks certain Web elements that could be used to record your behavior across sites.
• Control Center that contains site security and privacy controls.
• Indicator added to tabs that play audio with one-click muting.
• WebRTC improvements:
  • IPV6 support.
  • Preferences for controlling ICE candidate generation and IP exposure.
  • Hooks for extensions to allow/deny createOffer/Answer.
  • Improved ability for applications to monitor and control which devices are used in getUserMedia.
• Login Manager improvements:
  • Improved heuristics to save usernames and passwords.
  • Editing and showing all logins in line, Copy/Paste usernames/passwords from the Context menu.
  • Migration imports your passwords to Firefox from Google Chrome for Windows and Internet Explorer; import anytime from the Login Manager.
• Improved performance on interactive websites that trigger a lot of restyles.
• Implemented ES6 Reflect.
• Support for ImageBitmap and createImageBitmap().
• Media Source Extension for HTML5 video available for all sites.
• Viewing HTML source in a tab.
• Remote website debugging over WiFi (no USB cable or ADB needed).
• Asynchronous call stacks now allow web developers to follow the code flow through setTimeout, DOM event handlers, and Promise handlers.
• Configurable Firefox OS Simulator in WebIDE, to simulate reference devices like phones, tablets, even TVs.
• CSS filter presets in the Inspector.
• Ability to save filter presets inside CSS Filter Tooltip.

End-of-life 42.0.x product line on December 15, 2015.

• Private Browsing with Tracking Protection offers choice of blocking additional trackers.
• Improved API support for m4v video playback.
• Firefox 64-bit for Windows is now available via the Firefox download page.
• Users can choose search suggestions from the Awesome Bar.
• On-screen keyboard displayed on selecting input field on devices running Windows 8 or greater.
• Firefox Health Report has switched to use the same data collection mechanism as telemetry.
• Markup view shows indicators for pseudo-classes locked for elements.
• Binding F1 key to open the settings when the toolbox is focused.
• New 'Use in Console' context menu item in Inspector to store selected element in a temporary variable.
• Search button next to overridden CSS properties to find similar properties in the rules view.
• Ability to filter styles from their property names in the rules view.
• Stack traces are now shown for exceptions inside the console.
• Added ability to display server-side logs in the console.
• Ability to choose resolution for the GCLI screenshot command.
• Subresource integrity allows developers to make their sites more secure.
• Network requests in Console now link to Network panel instead of opening in a popup.
• Unprefixed 'hyphens' property is now supported.
• WebIDE now has a sidebar-based UI.
• The 'transform-origin' property is now supported on SVG elements.
• Animation inspector now displays animations in a timeline.
• Single-process mode is no longer supported for NPAPI plugins.
• Fixed an issue in which the Eyedropper tool does not work as expected when page is zoomed.
• Various security fixes.

Off-cycle stability update.^[421]

• Preparing to use SHA-256 signing certificate for Windows builds, to meet new signing requirement.

Off-cycle security and stability update.^[422]

• Use of a SHA-256 signing certificate for Windows builds, to meet new signing requirements.

Off-cycle stability update.^[423]

• Fixed network issue when using Nvidia's Network Access Manager.
• On some Windows configurations, improved the decoding of some videos on YouTube.

Off-cycle stability update.^[424]

• Fix for startup crash for users of a third party antivirus tool.
• Multi-user GNU/Linux download folders can be created.
• Re-enabled SHA-1 certificates.
• The last version to support HTTP cookie prompts.

End-of-life 43.0.x product line on January 26, 2016.

• This and newer versions erase the cookie permissions database of any previous Firefox version.

• Improved warning pages for certificate errors and untrusted connections.
• Enabled H.264 if system decoder is available.
• Enabled WebM/VP9 video support on systems that don't support MP4/H.264.
• In the animation-inspector timeline, lightning bolt icon next to animations running on the compositor thread.
• Support for the brotli compression format via HTTPS content-encoding.
• Screenshot commands allow user choice of pixel ratio in Developer Tools.
• Fixed an issue where Windows XP and Vista screensaver doesn't disable when watching videos.
• Various security fixes.
• To support unicode-range descriptor for webfonts, font matching under Linux now uses the same font matching code as other platforms.
• Use of a SHA-256 signing certificate for Windows builds, to meet new signing requirements.
• Firefox has removed support for the RC4 decipher.
• Firefox will no longer trust the Equifax Secure Certificate Authority 1024-bit root certificate or the UTN – DATACorp SGC to validate secure website certificates.
• Stricter validation of web fonts.
• On-screen keyboard support temporarily turned off for Windows 8 and Windows 8.1.
• Right-clicking on a logged object in the console to store it as a global variable on the page.
• Visual tools for Animation:.
  • View/Edit CSS animation keyframe rules directly in the inspector.
  • Visually modify the cubic-bezier curve that drives the way animations progress through time.
  • Discover and scrub through all CSS animations and transitions playing on the page.
  • Learn more: http://devtoolschallenger.com/.
• Visual tools for Layout and Styles:
  • Display rulers along the viewport to verify size and position and use the measurement tool to easily detect spacing and alignment problems.
  • Use CSS filters to preview and create real-time effects like drop-shadows, sepia, etc..
  • Learn more: http://devtoolschallenger.com/.
• New memory tool for inspecting the memory heap.
• Service Workers API.
• Built-in JSON reader to intuitively view, search, copy and save data without extensions.
• A jump to function definitions in the debugger with Cmd-Click.
• WebSocket Debugging API and add-on.
• The rule view now displays styles using their authored text, and edits in the rule view are now linked to the style editor.

Off-cycle stability update.^[428]

• Fixed an issue which could lead to the removal of stored passwords under certain circumstances.
• Allows spaces in cookie names.
• Requires NSS 3.21.
• Fixed a crash in cache networking.
• Fix for using WebSockets in service worker controlled pages.
• Disabled opus/vorbis audio with H.264.
• Shipment for the Gecko SDK.
• Fix for graphics startup crash on GNU/Linux.

• Fixed an issue where Firefox hangs or crashes on startup.

End-of-life 44.0.x product line on March 8, 2016.

• Instant browser tab sharing through Hello.
• Tabs synced via Firefox Accounts from other devices are now shown in dropdown area of Awesome Bar when searching.
• Synced Tabs button in button bar.
• Introduces a new preference (network.dns.blockDotOnion) to allow blocking .onion at the DNS level.
• Guarani [gn] locale added.
• URLs containing a Unicode-format Internationalized Domain Name (IDN) are now properly redirected.
• Various security fixes.
• Tab Groups (Panorama) feature removed.
• Ability to filter snapshot output in memory tool.
• Fine-tuning animations by changing the playback rate of animations in the animation-inspector's timeline.
• DOMContentLoaded and load events shown in the network monitor timeline.
• Added Negative url filtering for the network monitor.
• Support for diffing heap snapshots added to the memory tool.
• Inspector search now matches results from all content in the page, including subframes.
• List of animated properties and keyframes is now displayed when clicking on an animation in the animation-inspector’s timeline.
• Push API support, part of Progressive Web Applications.
• Support for delivery of a Content Security Policy (CSP) via a meta tag.
• Web Speech synthesis API.
• ES6 Classes.

• Last release for Android 3.0

End-of-life 45.0.x product line on April 26, 2016.

• Fix for a potential performance regression (YouTube for example).
• Fix for a regression causing search engine settings to be lost in some context.
• Brings back non-standard jar: URIs to fix a regression in IBM iNotes.
• Fixed an issue in which XSLTProcessor.importStylesheet was failing when <import> was used.
• Fix for an issue which could cause the list of search provider to be empty.
• Fix for a regression when using the location bar.
• Fix for some loading issues when Accept third-party cookies: was set to Never.
• Disabled Graphite font shaping library.

• Fix for an issue impacting the cookie header when third-party cookies are blocked.
• Fix for a web compatibility regression impacting the srcset attribute of the image tag.
• Fix for a crash impacting the video playback with Media Source Extension.
• Fix for a regression impacting some specific uploads.

Desktop

• Fix for a regression with the copy and paste with some old versions of some Gecko applications like Thunderbird.

• Fixed a build issue when jit is disabled.
• Fixed add-on signing certificate expiration.
• Fixed a graphics-related shutdown crash.

• Fixed graphics-related crashes.
• Fixed unicode support for AutoConfig API.
• Web compatibility fix for addEventListener API.

• Improved security of the JavaScript Just In Time (JIT) Compiler
• GTK3 integration (GNU/Linux only)
• Screen reader behavior with blank spaces in Google Docs corrected
• Corrected rendering for scaled SVGs that use a clip and a mask
• WebRTC fixes to improve performance and stability
• Display of dominator trees in Memory tool
• Allocation and garbage collection pause profiling in the performance panel
• Launch of responsive mode from the Style Editor @media sidebar
• Added support for document.elementsFromPoint
• Added HKDF support for Web Crypto API

• Fixed add-on signing certificate expiration.
• Fixed service worker update issue.
• Fixed a build issue when jit is disabled.
• Fixed a page loading issue related to antivirus software.
• Searched a plugin issue for various locales.
• Limited Sync registration updates.

End-of-life 46.0.x product line on June 7, 2016.

• Support for Google’s Widevine CDM on Windows and Mac OS X so streaming services like Amazon Video can switch from Silverlight to encrypted HTML5 video.
• Enabled VP9 video codec for users with fast machines
• Embedded YouTube videos now play with HTML5 video if Flash is not installed.
• Ability to view and search open tabs from your smartphone or another computer in a sidebar
• Allowed no-cache on back/forward navigations for https resources
• Latgalu [ltg] locale added.
• Various security fixes
• FUEL (Firefox User Extension Library) has been removed. Add-ons relying on it will stop working.
• The browser.sessionstore.restore_on_demand preference has been reset to its default value (true) to avoid e10s performance problems.
• The Firefox click-to-activate plugin whitelist has been removed.
• Web platform changes
• Ability to view, start, and debug registered Service Workers in the Service Workers developer tool
• Ability to simulate Push messages in the Service Workers developer tool
• 'Start' button for service workers in about:debugging to start registered Service Workers
• Changes that can affect add-on compatibility
• Added support for ChaCha20/Poly1305 cipher suites
• Custom user agents supported in Responsive Design Mode
• Smart multi-line input in the Web Console
• cuechange events are now available on TextTrack objects
• WebCrypto: PBKDF2 supports SHA-2 hash algorithms
• WebCrypto: RSA-PSS signature support

Android

• Last release to support Android 2.3.x (Gingerbread)

• Fixed an issue in which Selenium WebDriver may cause Firefox to crash at startup.

• Detect SSE hardware version.
• Detect Websense to protect users from a startup crash.

End-of-life 47.0.x product line on November 1, 2016.

• Roar for moar protection against harmful downloads! We've got your back.
• Process separation (e10s) is enabled for some of you. Like it? Let us know and we'll roll it out to more.
• Add-ons that have not been verified and signed by Mozilla will not load.
• GNU/Linux fans: Get better Canvas performance with speedy Skia support. Try saying that three times fast.
• WebRTC embetterments:
  • Delay-agnostic AEC enabled.
  • Full duplex for GNU/Linux enabled.
  • ICE Restart & Update is supported.
  • Cloning of MediaStream and MediaStreamTrack is now supported.
• Searching for something already in your bookmarks or open tabs? We added super smart icons to let you know.
• Tab (move buttons) and Shift+F10 (pop-up menus) now behave as they should in Firefox customization mode (Windows only).
• The media parser has been redeveloped using the Rust programming language.
• Heyo, Jabra & Logitech C920 webcam users. Fixed WebRTC bugs causing frequency distortions.
• Improved step debugging on last line of functions.
• After version 48, SSE2 CPU extensions are going to be required on Windows.
• Au revoir to Windows Remote Access Service modem Autodial.
• WebExtensions support is now considered as stable.
• Want to move absolute & fixed positioned elements? Now you can with our geometry editor.
• The memory tool now has a tree map view for your debugging pleasure.
• We're putting the spotlight on the background. Now you can debug WebExtensions background content scripts and background pages.
• Content Security Policy (CSP) is now enforced for WebExtensions.
• Old and busted: Error Console. New hotness: Browser Console for your debugging pleasure.
• Add-on development just got easier because you can reload them from about:debugging — because we're all about debugging.
• This theme is hot, hot, hot! Say hi to the Firebug theme for Developer Tools.
• Expanded network requests from the console panel to view request details in line, so you can see things in context.
• Workers can now use the Web Crypto API.

• Fix for an audio regression impacting some major websites.
• Fix for a top crash in the JavaScript engine.
• Fix for a startup crash issue caused by Websense.
• Fix for a different behavior with e10s / non-e10s on <select> and mouse events.
• Fix for a top crash caused by plugin issues.
• Fix for an unsigned add-ons issue on Windows.
• Fix for a shutdown issue.
• Fix for a crash in WebRTC.

• Fix for a startup crash issue caused by Websense (Windows only).
• Last release for Mac OS X 10.6-10.8.

End-of-life 48.0.x product line on September 20, 2016.

• Updated Firefox Login Manager to allow HTTPS pages to use saved HTTP logins. It’s one more way Firefox is supporting Let’s Encrypt and helping users transition to a more secure web.
• Added features to Reader Mode that make it easier on the eyes and the ears.
  • Controls that allow users to adjust the width and line spacing of text.
  • Narrate, which reads the content of a page out loud.
• Improved video performance for users on systems that support SSSE3 without hardware acceleration.
• Added context menu controls to HTML5 audio and video that let users loops files or play files at 1.25x speed.
• Improved performance on OS X systems without hardware acceleration.
• Improved appearance of anti-aliased OS X fonts.
• Improvements in about:memory reports for tracking font memory usage.
• Improved performance on Windows systems without hardware acceleration.
• Fixed an issue that prevented users from updating Firefox for Mac unless they originally installed Firefox. Now, those users as well as any user with administrative credentials can update Firefox.
• Ended Firefox for Mac support for OS X 10.6, 10.7, and 10.8.
• Ended Firefox for Windows support for SSE processors.
• Removed Firefox Hello.
• Re-enabled the default for Graphite2 font shaping.
• Added a Cause column to the Network Monitor to show what caused each network request.
• Introduced web speech synthesis API.

• Mitigated a startup crash issue caused by Websense (Windows only).

• Asynchronous rendering of the Flash plugins is now enabled by default. This should improve performance and reduce crashes for sites that use the Flash plugin.
• Changed D3D9 default fallback preference to prevent graphical artifacts.
• Fixed a network issue that prevents some users from seeing the Firefox UI on startup.
• Fixed a web compatibility issue with Array.prototype.values
• Fixed a web compatibility issue with file uploads.
• Diagnostic information on timing for tab switching.
• Fix for a Canvas filters graphics issue affecting HTML5 apps.

End-of-life 49.0.x product line on November 15, 2016.