Firefox was created by Dave Hyatt and Blake Ross as an experimental branch of the Mozilla browser, first released the Firefox 1.0 on November 9, 2004. Since version 5.0, a rapid release cycle was put into effect, resulting in a new major version release every six weeks on Tuesday. Firefox 68 is the latest version released on July 9, 2019.
The project that became Firefox today began as an experimental branch of the Mozilla Suite called m/b (or mozilla/browser). Firefox retains the cross-platform nature of the original Mozilla browser, using the XULuser interface markup language. The use of XUL makes it possible to extend the browser's capabilities through the use of extensions and themes. The development and installation processes of these add-ons raised security concerns, and with the release of Firefox 0.9, the Mozilla Foundation opened a Mozilla Update website containing "approved" themes and extensions. The use of XUL sets Firefox apart from other browsers, including other projects based on Mozilla's Geckolayout engine and most other browsers, which use interfaces native to their respective platforms (Galeon and Epiphany use GTK+, K-Meleon uses MFC, and Camino uses Cocoa). Many of these projects started before Firefox, and probably served as inspiration.
Phoenix and Firebird
Phoenix 0.1, the first official release
Hyatt, Ross, Hewitt and Chanial developed their browser to combat the perceived software bloat of the Mozilla Suite (codenamed, internally referred to, and continued by the community as SeaMonkey), which integrated features such as IRC, mail, news, and WYSIWYGHTML editing into one internet suite. After it was sufficiently developed, binaries for public testing appeared in September 2002 under the name Phoenix. This name carried the implication of the mythical firebird that rose triumphantly from the ashes of its dead predecessor, in this case Netscape Navigator which lost the "First browser war" to Microsoft's Internet Explorer. The name Mozilla began as the internal codename for the original 1994 Netscape Navigator browser aiming to displace NCSA Mosaic as the world's most popular web browser. The name for this would-be "Mosaic killer" was meant to evoke the building-crushing Godzilla. The name Mozilla was revived as the 1998 open sourcing spinoff organization from Netscape.
The name Phoenix remained until April 14, 2003, when it was changed because of a trademark dispute with the BIOS manufacturer Phoenix Technologies (which produces a BIOS-based browser called Phoenix FirstWare Connect). The new name, Firebird, met with mixed reactions, particularly as the Firebird database server already carried the name. In response, the Mozilla Foundation stated that the browser should always bear the name Mozilla Firebird to avoid confusion with the database software.
Early description of what cookies are in Preferences window of Mozilla Firefox 0.9.3. This description was soon dropped in later versions.
Firefox 1.0, the first release targeted for general public
Due to continuing pressure from the Firebird community, on February 9, 2004 the project was renamed again to Mozilla Firefox. The name "Firefox" (a reference to the red panda) was chosen for its similarity to "Firebird", and its uniqueness in the computing industry. To ensure that no further name changes would be necessary, the Mozilla Foundation began the process of registering Firefox as a trademark with the United States Patent and Trademark Office in December 2003. This trademark process led to a delay of several months in the release of Firefox 0.8 when the foundation discovered that Firefox had already been registered as a trademark in the UK for Charlton Company software. The situation was resolved when the foundation was given a license to use Charlton's European trademark.
Firefox version 1.0 was released on November 9, 2004. The launch of version 1.0 was accompanied by "a respectable amount of pre-launch fervor" including a fan-organized campaign to run a full-page ad in The New York Times.
Although the Mozilla Foundation had intended to make the Mozilla Suite obsolete and replace it with Firefox, the Foundation continued to maintain the suite until April 12, 2006 because it had many corporate users and was bundled with other software. The Mozilla community (as opposed to the Foundation) continues to release new versions of the suite, using the product name SeaMonkey to avoid confusion with the original Mozilla Suite.
"Deer Park", the codename of the Firefox 1.1 and 1.5 Alphas, did not include Firefox branding.
Firefox 1.5 was released on November 30, 2005. Originally, it was planned to have a version 1.1 at an earlier date as the new Firefox version after 1.0, with development on a later version (1.5) in a separate development branch, but during 2005 both branches and their feature sets were merged (the Mozilla Foundation abandoned the 1.1 release plan after the first two alpha builds), resulting in an official release date between the original dates planned for both versions.
Version 1.5 implemented a new Mac-like options interface, the subject of much criticism from Microsoft Windows and Linux users, with a "Sanitize" action to allow someone to clear their privacy-related information without manually clicking the "Clear All" button. In Firefox 1.5, a user could clear all privacy-related settings simply by exiting the browser or using a keyboard shortcut, depending on their settings. Moreover, the software update system was improved (with binary patches now possible). There were also improvements in the extension management system, with a number of new developer features. In addition, Firefox 1.5 had preliminary SVG 1.1 support.
Behind the screens, the new version resynchronized the code base of the release builds (as opposed to nightly builds) with the core "trunk", which contained additional features not available in 1.0, as it branched from the trunk around the 0.9 release. As such, there was a backlog of bug fixes between 0.9 and the release of 1.0, which were made available in 1.5.
There were also changes in operating system support. As announced on 23 June 2005 by the Mozilla Foundation, Firefox 1.1, which later became 1.5, and other new Mozilla products did no longer support Mac OS X v10.1, in order to improve the quality of Firefox releases on Mac OS X v10.2 and above. Firefox 1.5 was the final version supported on Windows 95.
Alpha builds of Firefox 1.5 (id est, 1.1a1 and 1.1a2) did not carry Firefox branding; they were labelled "Deer Park" (which was Firefox 1.5's internal codename) and contained a different program icon. This was done to dissuade end-users from downloading preview versions, which are intended for developers only.
In December 2007, Firefox Live Chat was launched. It allowed users to ask volunteers questions through a system powered by Jive Software, with guaranteed hours of operation and the possibility of help after hours.
Firefox 220.127.116.11 was the final version that could run under an unmodified installation of Windows NT 4.0, Windows 98, and Windows ME.[failed verification] Subsequently, Mozilla Corporation announced it would not develop new versions of Firefox 2 after the 18.104.22.168 release, but continued Firefox 2 development as long as other programs, such as Thunderbird mail client, depended on it. The final internal release was 22.214.171.124, released in late April 2009.
Anti-phishing protection. Search suggestions appear with search history in the search box for Google and Yahoo!. Support for client-side session and persistent storage.
Changes during betas
New Winstripe theme refresh: new navigation icons, URL bar refresh (new Go button attached to the URL bar), Search bar refresh, Tab bar refresh, Alltabs button (used to view a popup list of all tabs open).
Firefox 3 was released on June 17, 2008, by the Mozilla Corporation. Firefox 3 uses version 1.9 of the Mozilla Gecko layout engine for displaying web pages. This version fixes many bugs, improves standard compliance, and implements new web APIs. Other new features include a redesigned download manager, a new "Places" system for storing bookmarks and history, and separate themes for different operating systems.
Development stretches back to the first Firefox 3 beta (under the codename 'Gran Paradiso') which had been released several months earlier on November 19, 2007, and was followed by several more beta releases in spring 2008 culminating in the June release. Firefox 3 had more than 8 million unique downloads the day it was released, setting a Guinness World Record.
Effective top-level domain (eTLD) service better restricts cookies and other restricted content to a single domain.
Better protection against cross-site JSON data leaks.
Easier password management – save passwords after successful login
Simplified add-on installation from third party’s
New Download Manager
Resumable downloading after closing the browser
Full page zoom
Podcasts and Videocasts can be associated with your media playback tools
Tab scrolling and quickmenu
Save what you were doing – Firefox 3 will prompt users to save tabs on exit.
Optimized Open in Tabs behavior
Location and Search bar size can now be customized with a simple resizer item.
Text selection improvements (select multiple selections of text)
Find toolbar: the Find toolbar now opens with the current selection.
Plugin management with the add-on manager
Improved integration with Windows
Improved integration with the Mac
Integration with Linux GTK theme
Bookmark star button
Smart Location Bar
Library of bookmarks, history, etc.
Smart Bookmark Folders
Web-based protocol handlers for mail:to
Download & Install Add-ons from the Add-on manager
Easy to use Download Actions
New graphics and font handling in Gecko 1.9 provide rendering improvements in:
Display of fonts with ligatures and complex scripts
Color management of images with capabilities
Offline support for web applications
Reduced memory usage
25000 total code changes
Changes during alphas
Cairo graphics library. Cocoa Widgets in OS X builds. Updated threading model. Changes to how DOM events are dispatched, how HTML object elements are loaded, and how web pages are painted. New SVG elements and filters, and improved SVG specification compliance. Windows 95, 98, ME and Mac OS X v10.2 no longer supported. Moving DOM nodes between documents require a call to importNode or adoptNode as per the DOM specification.
Support for allowing web pages to store resources in the browser's offline cache. Support for Animated PNG images. Support for the "HTTPOnly" cookie extension which provides enhanced cookie privacy (also backported to Firefox 126.96.36.199). Improvements to layout and scaling precision across numerous screen and printer resolutions.
Places (bookmark and history service based on SQLite) used by default, but no front-end changes. Breakpad used as crash reporter on Windows and Mac OS X, superseding closed-source Talkback. Password manager rewrite. Support for Growl and native widgets within forms for Mac OS X.
Upgrade of SQLite to version 3.3.17, leading to increased cookie performance due to transition of cookie service to SQLite. Site-specific preference service, used initially for text zoom, allowing zoom setting to remain on each website. Support for native widgets within forms for Linux. New Quit dialog handles multiple windows more elegantly and allows users to save session. Autoscroll rewrite: numerous bug fixes and significant performance gain. Fixes to the use of units within the download manager. Various Places bug fixes.
More APIs implemented from WHATWG specs, such as ability to read files from file selection fields without need to upload and cut/copy/paste events, and cross-site XMLHttpRequest. New protocol-handling dialog. Experimental full-page zoom support, but no UI to control it. Numerous Mac OS X bug fixes, but Mac OS X 10.3 no longer supported for Gecko 1.9. General bug fixes.
New, basic UI for tagging bookmarks. Remember password prompt changed to non-modal information bar. Malware blacklist support. New UI for FTP and File protocol listings. Applications pane added to preferences. Basic support for web-based protocol handlers.
Changes during betas
New UI improvements, including redesigned location bar, Places Organizer, Smart Bookmarks. Various stability and performance improvements.
New UI improvements, including redesigned buttons and location bar. Different default native themes for each operating system. Upgraded to SQLite 3.5.4. Various stability and performance improvements.
New UI improvement, including improved default themes for different operating systems. Various improvements in speed and resource usage.
Available in 64 languages.
Improved new Private Browsing Mode.
Improvements to web worker thread support.
New native JSON support.
Improvements to Gecko layout engine, including speculative parsing for faster content rendering.
Available in 70 languages.
Improved tools for controlling private data, including Private Browsing Mode.
Ability to provide Location Aware Browsing using web standards for geolocation.
Support for native JSON, and web worker threads.
Improvements to Gecko layout engine, including speculative parsing for faster content rendering.
Version 3.6, released on January 21, 2010, uses the Gecko 1.9.2 engine and includes several interface improvements, such as "personas". This release was referred to as 3.2 before 3.1 was changed to 3.5. The codename for this version was Namoroka. This is the last major, official version to run on PowerPC-based Macintoshes.
One minor update to Firefox 3.6, version 3.6.4 (code-named Lorentz) is the first minor update to make non-intrusive changes other than minor stability and security fixes. It adds Out of Process Plugins (OOPP), which runs plugins in a separate process, allowing Firefox to recover from plugin crashes. Firefox 3.6.6 lengthens the amount of time a plugin is allowed to be unresponsive before the plugin quits.
Protection from out-of-date plugins to keep users safer as they browse.
Open, native video can now be displayed full screen and supports poster frames.
The ability for web developers to indicate that scripts should run asynchronously to speed up page load times.
Continued support for downloadable web fonts using the new WOFF font format.
Support for new CSS attributes such as gradients, background sizing, and pointer events.
Support for new DOM and HTML5 specifications including the Drag & Drop API and the File API, which allow for more interactive web pages.
Changes to how third-party software can integrate with Firefox in order to prevent crashes.
Changes during alphas
Compositor (Phase 1), which moves Gecko to using one native widget per top-level content document.
A new focus model.
The chromedir attribute has been replaced with a pseudoclass.
Several new CSS3 properties including background size and gradients for background images.
Startup and responsiveness improvements throughout the application.
Changes during betas
A mechanism to prevent incompatible software from crashing Firefox.
A change to how third-party software integrates with Firefox to increase stability. The ability to run scripts asynchronously to speed up page load times.
Regular security and stability update. Also added support for X-FRAME-OPTIONS HTTP response header to help prevent clickjacking and removed option to enable experimental HTML5 parser via user preference html5.enable in about:config.
On October 13, 2006, Brendan Eich, Mozilla's then Chief Technology Officer, wrote about the plans for "Mozilla 2", referring to the most comprehensive iteration (since its creation) of the overall platform on which Firefox and other Mozilla products run. Most of the objectives were gradually incorporated into Firefox through versions 3.0, 3.5, and 3.6. The largest changes, however, were planned for Firefox 4.
Core Animation rendering model for plugins on Mac OS X
Web developers can update the URL field without reloading the page using HTML History APIs
More responsive page rendering using lazy frame construction
Link history lookup is done asynchronously to provide better responsiveness during pageload
CSS :visited selectors have been changed to block websites from being able to check a user's browsing history
New HTML5 parser
Support for more HTML5 form controls
Web authors can now get touch events from Firefox users on Windows 7 machines
Changes during alphas
Support for WebGL(Disabled by default, but can be enabled by changing a preference). Support for new CSS, DOM and HTML5 web technologies.
An experimental Direct2D rendering backend on Windows is available, turned off by default. Significant API improvements are available for JS-ctypes. Mozilla now uses an infallible allocator. Additional fixes for multi-process plugins.
CSS :visited selectors have been changed to block ways that websites can quickly check a user's browsing history. Currently loaded web pages are shown in the location bar autocomplete list, allowing switching to existing tabs. The beta version of Adobe Flash is now run in a separate process on Mac OS X Snow Leopard (10.6). Full-screen video on Windows is now rendered using hardware acceleration when available. Mozilla has implemented the Core Animation rendering model for plugins on Mac OS X. Linux builds are now built with -fomit-frame-pointer. Support for new SVG and HTML5 web technologies.
Added WebM video playback.
Changes during betas
Tabs are now on top by default on Windows. On Windows Vista and Windows 7 the menu bar has been replaced with the Firefox button. The Bookmarks Toolbar has been replaced with a Bookmarks Button by default (you can switch it back if you'd like). Support for more HTML5 technologies.
Support for the new proposed Audio Data API. Direct2D Hardware Acceleration is now on by default for Windows 7 users. Firefox button has a new look for Windows Vista and Windows 7 users. Support for HSTS security protocol allowing sites to insist that they only be loaded over SSL.
Fixed a stability issue affecting Windows users. Fixed an issue causing rendering errors with plugins affecting Mac OS X users.
The Firefox Sync setup experience has been greatly improved across desktop and mobile devices. Speed, functionality, and compatibility improvements to WebGL. Additional polish for the Firefox Add-ons Manager.
Overhaul of the bookmarks and history code, enabling faster bookmarking and startup performance. Per-compartment garbage collection is now enabled, reducing work done during complex animations.
Compatibility and stability improvements when using Adobe Flash on Mac OS X. Improvements in memory usage. Support for a graphics driver blacklist to improve stability.
Support for the proposed Do Not Track ("DNT") header. Connection status messages are now shown in a small overlay. WebGL has been re-enabled on Linux. The default homepage design has been refreshed. Firefox no longer switches into offline mode automatically.
Increased performance while viewing Flash content. Improved plugin compatibility with hardware acceleration enabled. Hovering over links now displays the URL at the bottom of the window rather than in the location bar. General stability, performance, and compatibility improvements.
Changes during release candidates
General stability, performance, and compatibility improvements.
Blacklisted a few invalid HTTPS certificates.
Updated localizations for 29 locales.
Added Vietnamese localization, bringing the total languages available in Firefox 4 to 83.
In April 2011, the development process was split into several "channels", each working on a build in a different stage of development. The most recent available build is called "Nightly Builds" and offers the latest, untested features and updates. The "Aurora" build is up to six weeks behind "Nightly" and offers functionality that has undergone basic testing. As of version 35, the "Aurora" channel has been renamed to the "Developer Edition" channel. The "Beta" channel is up to six weeks behind the "Aurora" build, for up to about twelve week period compared to the most recent "Nightly" build. The "Beta" channel provides improved stability over the "Nightly" builds and is the first development milestone that has the "Firefox" logo. "Release" is the current official version of Firefox. Gecko version numbering is same as Firefox build version number, starting 5.0 on Firefox 5.
The stated aim of this faster-paced process is to get new features to users faster. This accelerated release cycle was met with criticism by users, as it often broke add-on compatibility, as well as those who believe Firefox was simply trying to increase its version number to compare with other browsers such as Google Chrome.
Firefox 5 through 9
Firefox 5 was released on June 21, 2011, three months after the major release of Firefox 4. Firefox 5 is the first release in Mozilla's new rapid release plan, matching Google Chrome's rapid release schedule and rapid version number increments. Firefox 5 has significantly improved the speed of web-related tasks, such as loading pages with combo boxes or MathML. Mozilla also integrated the HTML5 videoWebM standard into the browser, allowing playback of WebM video.
Firefox 7 released on September 27, 2011, uses as much as 50% less RAM than Firefox 4 as a result of the MemShrink project to reduce Firefox memory usage.
Firefox 7.0.1 was released a few days later, fixing a rare, but serious, issue with add-ons not being detected by the browser. Some URLs are trimmed in the address bar, so the "http://" scheme no longer appears, but "https://" is still displayed. Trailing slashes on domains are also hidden, for example: https://www.example.org/ becomes https://www.example.org.
Firefox 8 released on November 8, 2011 prompts users about any previously installed add-ons. Upon installation, a dialog box prompted users to enable or disable the add-ons. Add-ons installed by third-party programs were disabled by default, but user-installed add-ons were enabled by default. Mozilla judged that third-party-installed add-ons were problematic, taking away user control, lagging behind on compatibility and security updates, slowing down Firefox startup and page loading time, and cluttering the interface with unused toolbars.
Firefox 10 and Firefox ESR 10 were released on January 31, 2012. Firefox 10 added a full screen API and improved WebGL performance, support for CSS 3D Transforms and for anti-aliasing in the WebGL standard for hardware-accelerated 3D graphics. These WebGL updates mean that more complex site and Web app animations can render smoothly in Firefox, and that developers can animate 2D objects into 3D without plug-ins. It also introduced a new CSS Style Inspector, which allow users to check out a site's structure and edit the CSS without leaving the browser. Firefox 10 assumed all add-ons made for at least Firefox 4 were compatible. The add-on developer is able to alert Mozilla that the add-on is incompatible, overriding compatibility with version 10 or later. This new rule also does not apply to themes.
Firefox 10 ESR is the first Extended Support Release (ESR) as previously in January 10, 2012, where the Mozilla Foundation announced the availability of an ESR version of Firefox. Firefox ESR is intended for groups who deploy and maintain the desktop environment in large organizations such as universities and other schools, county or city governments and businesses. During the extended cycle, no new features will be added to a Firefox ESR; only high-risk/high-impact security vulnerabilities or major stability issues will be corrected.
Firefox 11 was released on March 13, 2012. Firefox 11 introduced many new features, including migration of bookmarks and history from Google Chrome,SPDY integrated services, Page Inspector Tilt (3D View), Add-onSync, redesigned HTML5 video controls, and the Style Editor (CSS). The update also fixed many bugs, and improved developer tools.
Firefox 12 was released on April 24, 2012. Firefox 12 introduced few new features, but it made many changes and laid the ground work for future releases. Firefox 12 for Windows added the Mozilla Maintenance Service which can update Firefox to a newer version without UAC prompt. It also added line numbers in the "Page Source" and centered find in page results. There were 89 improvements to Web Console, Scratchpad, Style Editor, Page Inspector, Style Inspector, HTML view and Page Inspector 3D view (Tilt). Many bugs were fixed, as well as many other minor under-the-hood changes. Firefox 12 is the final release to support Windows 2000 and Windows XP RTM & SP1.
Firefox 13 was released on June 5, 2012. Starting with this version, Windows support was exclusively for Windows XP SP2/SP3, Windows Vista, and Windows 7. Firefox 13 adds and updates several features, such as an updated new tab and home tab page. The updated new tab page is a feature similar to the Speed Dial already present in Opera, Google Chrome, Apple Safari, and Internet Explorer. The new tab page will display nine of the user's most visited websites, along with a cached image. In addition to the updated new tab and home tab page, Mozilla has added a user profile cleaner/reset, reduced hang times, and implemented tabs on demand. The user profile cleaner/reset provides a way for users to fix Firefox errors and glitches that may occur. Mozilla's tabs on demand restores tabs that were open in the previous session, but will keep the tabs unloaded until the user requests to view the page.
Firefox 14 version 14.0 was released on June 26, 2012 for mobiles only, just outside the regular release schedule of the web browser. In order to sync the version numbers of the desktop and mobile version of Firefox, Mozilla decided to release version 14.0.1 for both mobile and desktop on July 17, 2012, instead of Firefox 14 version 14.0 for the desktop and version 14.0.1 for mobiles.
Firefox 14 introduces a new hang detector (similar to how Mozilla currently collects other data) allows Mozilla to collect, analyze, and identify the cause of the browser freezing/hanging. Mozilla will use this information to improve the responsiveness of Firefox for future releases. In addition to tackling freezing and not-responding errors that occur because of Firefox, Mozilla implemented opt-in activation for plugins such as Flash and Java. Mozilla wants to reduce potential problems that could arise through the unwanted use of third-party applications (malware, freezing, etc.).
Firefox 15 introduced silent updates, an automatic update that will update Firefox to the latest version without notifying the user, a feature that the web browsers Google Chrome and Internet Explorer 8 and above have already implemented, although the user was able to disable that function. The startup time in Firefox 15 was improved for Windows users.
Firefox 16 was released on October 9, 2012, fixing outstanding bugs of the new features in Mac OS X Lion. There was an improvements made to startup speed when a user wants to restore a previous session. Support for viewing PDF files inline was added in placement of a plugin. Support for web apps was added. Opus audio format is now enabled by default.
The roll-out of Firefox 16 revision 16.0.0 was stopped on October 10, 2012, after Mozilla detected a security flaw and recommended downgrading to 15.0.1 until the issue could be fixed. The security flaw was fixed in version 16.0.1, which was released the following day, October 11, 2012.
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.
Optional Gstreamer backend for HTML5 video to allow H.264 playback.  This allows playback of H.264 if the codec is installed as a GStreamer plugin. GStreamer support is not enabled in the official builds, but can be enabled at compile time.
Firefox 17 and Firefox ESR 17 were released on November 20, 2012. It was not planned to bring as many user-facing features as previous releases, it brings improved display of location bar results, improvements to the silent update mechanism for users with incompatible add-ons, and refinements to the Click-To-Play system introduced in Firefox 14. A new feature for developers, an HTML tree editor is also included. Firefox 17 is the first version of the browser that uses SpiderMonkey 17.
Firefox 19 was released on February 19, 2013, featuring a built-in PDF viewer.
Firefox 20 was released on April 2, 2013, introduced a panel-based download manager, along with H.264 decoding on the <video> tag (on Windows only), and per-window private browsing (per-tab private browsing on Android). It also includes a new developer toolbox, that combines all developer tools into one panel.
Firefox 21 was released on May 14, 2013. The Social API now supports multiple providers, enhanced three-state UI for Do Not Track (DNT). 
Firefox 22 was released on June 25, 2013. WebRTC is now enabled by default.
Firefox 29 with Australis interface, running on Windows 8.1
Firefox 24 and Firefox 24 ESR were released on September 17, 2013. The release includes support for the new scrollbar style in Mac OS X 10.7 (and newer), closing tabs to the right, an improved browser console for debugging, and improved SVG rendering, among other things. It is the first version of the browser that uses SpiderMonkey 24.
Firefox 25 was released on October 29, 2013. Firefox 25 Nightly was at one point slated to include the Australis theme, but Australis did not actually land on Nightly until Firefox 28, did not make it to Firefox 28 Aurora channel, and was finally available with Firefox 29. This release added support for <iframe srcdoc> attribute, background-attachment:local in CSS, along with Web audio API support, separate find bar for each tab and many other bug fixes.
Firefox 26 was released December 10, 2013. Firefox 26 changed the behavior of Java plugins to "click-to-play" mode instead of automatically running them. It also added support for H.264 on Linux, password manager support for script-generated fields, and the ability for Windows users without advanced write permissions to update Firefox, as well as many bug fixes and developer-related changes.
Firefox 27 was released on February 4, 2014. It adds improved Social API and SPDY 3.1 support, as well as enabling of TLS 1.1 and 1.2 by default. Also, it brings many bug fixes, security improvements, and developer-related changes.
Firefox 28 was released on March 18, 2014. It added support for VP9 video decoding and support for Opus in WebM. For Android, features such as predictive lookup from the address bar, quick share buttons and support for OpenSearch were added.
Firefox 29 was released on April 29, 2014 and includes the Australis interface, it also removes the add-on bar and moves its content to the navigation bar.
Firefox 30 was released on June 10, 2014. It adds support for GStreamer 1.0 and a new sidebar button, and most plugins are not activated by default.
Firefox 31 and Firefox 31 ESR were released on July 22, 2014. Both versions added search field on the new tab page and were improved to block malware from downloaded files, along with other new features. Firefox 31 ESR is the first ESR to include the Australis interface, unifying the user experience across different Firefox versions. Firefox 24.x.x ESR versions will be automatically updated to ESR version 31 after October 14, 2014.
Firefox 32 was released on September 2, 2014. It shows off HTTP caching improvements, adds HiDPI/Retina support in the Developer Tools UI and widens HTML5 support, among other things.
Firefox 33 was released on October 14, 2014. It now has off-main-thread compositing (OMTC) enabled by default on Windows (which brings responsiveness improvements),OpenH264 support, search suggestions on about:home and about:newtab, address bar search improvements, session restore reliability improvements, and other changes.
Firefox 33.1 was released on November 10, 2014, celebrating Firefox's 10-year anniversary. Firefox 33.1.1 was released for desktop only on November 14, 2014, fixing a startup crash.
The logo of Firefox Hello.
Firefox 34 was released on December 1, 2014. It brings Firefox Hello (a WebRTC client for voice and video chat), an improved search bar, and the implementation of HTTP/2 (draft14) and ALPN, together with other features. It also disables SSLv3, and enables the ability to recover from a locked Firefox process and to switch themes and personas directly in the customization mode.
Firefox 35 was released on January 13, 2015. It brings support for a room-based conversations model to the Firefox Hello chat service, and other functions, it includes security fixes.
Firefox 36 was released for desktop on February 24, 2015, bringing full HTTP/2 support and other smaller improvements and fixes. It was also released for Android three days later on February 27, 2015, adding support for the tablet user interface.
Firefox 37 was released on March 31, 2015, bringing a heartbeat user rating system, which provides user feedback about the Firefox, and improved protection against website impersonation via OneCRL centralized certificate revocation. Also, Bing search is changed to use HTTPS for secure searching, and added is support for opportunistic encryption of the HTTP traffic where the server supports HTTP/2's AltSvc feature.
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.
Both Firefox 38 and Firefox 38 ESR were released on May 12, 2015, with new tab-based preferences, Ruby annotation support and availability of WebSockets in web workers, along with the implementation of the BroadcastChannel API and other features and security fixes.
Firefox 39 was released on July 2, 2015 for desktop and Android, disabling insecure SSLv3 and RC4, improving performance for IPv6 fallback to IPv4 and including various security fixes. Firefox 39.0.3 was released on August 6, 2015, to fix a zero-day exploit.
Firefox 40 was released on August 11, 2015 for desktop and Android. On Windows 10, the Australis theme was updated to reflect the overall appearance of Windows 10, and the interface is adapted for usability on touchscreens when used in the operating system's "Tablet mode". Firefox 40 includes additional security features, including the filtering of pages that offer potentially unwanted programs, and warnings during the installation of unsigned extensions; in future versions, signing of extensions will become mandatory, and the browser will refuse to install extensions that have not been signed. Firefox 40 also includes performance improvements, such as off-main-thread compositing on Linux.
Firefox 41 was released on September 22, 2015 for desktop and Android. Among many additions are the ability to set a profile picture for a Firefox account, enhanced IME support using Text Services Framework, and instant messaging on Firefox Hello.
Firefox 42 was released on November 3, 2015 for desktop and Android. Among many additions are private browsing with tracking protection, IPv6 support in WebRTC, and the ability to view HTML source in a tab.
Firefox 43 was released on December 15, 2015 for desktop and Android. Among many additions are the availability of the 64-bit version for Windows 7 and above, a new strict blocklist, and audio indicators on Android.
Firefox 44 was released on January 26, 2016 for desktop and Android. Among many additions are the improvement of warning pages for certificate errors and untrusted connections, enabling of H.264 and WebM/VP9 video support on systems that don't support MP4/H.264, support for the brotli compression format via HTTPS content-encoding, and the use of Android print service to enable cloud printing. "Ask me every time" cookies option was removed without any notifications.
Firefox 45 and Firefox 45 ESR were released on March 8, 2016 for desktop (both) and Android (no ESR). Among many additions were Instant Browser sharing through Hello, the addition of Guarani locale, the ability to filter snapshot output in memory tool, and the removal of Tab Groups (panorama) feature.
Firefox 47 was released on June 7, 2016 for both desktop and Android. Among the many additions were 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; enabling VP9 video codec for users with fast machines; the ability of embedded YouTube videos to play with HTML5 video if Flash is not installed; and the addition of the Latgalian language. It is also the last Firefox version to support Android 2.3.x.
Firefox 48 was released on August 2, 2016 for both desktop and Android. Among the many additions were enhanced download protection and the removal of Windows Remote Access Service modem Autodial. It was also the first official release with "Electrolysis" (multi-process Firefox, meaning that the interface and web pages are running in separate processes in the computer) was enabled for part of the users.
Firefox 49 was released on September 20, 2016 for both desktop and Android. Among the many additions were an updated Firefox Login Manager, improved video performance for users on systems that support SSE3 without hardware acceleration, added context menu controls to HTML5 audio and video that let users loop files or play files at 1.25x speed, improvements in about:memory reports for tracking font memory usage, and the removal of Firefox Hello. The macOS version now requires at least OS X Mavericks, and the Microsoft Windows version requires a CPU which supports SSE2.
Firefox 50 was released on November 15, 2016 for both desktop and Android. Among the many additions were playback video on more sites without plugins with WebM EME Support for Widevine on Windows and Mac, improved performance for SDK extensions or extensions using the SDK module loader; download protection for a large number of executable file types on Windows, macOS, and Linux, increased availability of WebGL to more than 98 percent of users on Windows 7 and newer (desktop), and support for HLS videos via player overlay (Android).
Firefox 51 was released on January 24, 2017 for both desktop and Android. Among the many additions were added support for FLAC (Free Lossless Audio Codec) playback, better Tab Switching, support for WebGL 2, and a warning that is displayed when a login page does not have a secure connection.
Firefox 52 and Firefox 52 ESR were released on March 7, 2017 for desktop (both) and Android (no ESR). An important aspect of Firefox ESR 52.0 is that it is the first ESR version based on Firefox Electrolysis (Firefox 48) code base. Firefox 52 added support for WebAssembly (while disabled in Firefox ESR 52), an emerging standard that brings near-native performance to Web-based games, apps, and software libraries without the use of plugins; automatic captive portal detection, for easier access to Wi-Fi hotspots; user warnings for non-secure HTTP pages with logins (desktop); and display of media controls to pause or resume playback on the Android notification bar. Firefox 52 dropped support for NPAPI plugins like Microsoft Silverlight and Java with the exception of Adobe Flash Player (except the ESR version which still supports NPAPI).
Firefox 53 was released on April 19, 2017 for both desktop and Android. Starting with Firefox 53, Microsoft Windows support is exclusively for Windows 7 and above. Among the many additions are: improved graphics stability for Windows users with the addition of compositor process separation, light and dark "compact" themes available, based on the Firefox Developer Edition theme, removal of support for 32-bit macOS and Linux support for processors older than Pentium 4 and AMD Opteron; new visual design for audio and video controls, support for WebM video with alpha compositing, which allows playing videos with transparent backgrounds (desktop), Reader Mode displaying estimated reading time for the page (desktop and Android), and enabling two columns tabs setting in portrait mode (Android).
Firefox 54 was released on June 13, 2017 for both desktop and Android. Among the many additions are: simplifying the download button and download status panel, added support for multiple content processes, and the ability to create and save custom devices in Responsive web design mode (desktop), and improved audio and video playback in the browser, and improved bookmarks sync performance (Android).
Firefox 55 was released on August 8, 2017 for both desktop and Android. Among the many additions are: the launch of Windows support for WebVR, bringing immersive experiences to the web, options that let users optimize recent performance improvements, simplification of installation process with a streamlined Windows stub installer, improvement of address bar functionality, simplification of printing from Reader Mode (desktop), and the option to accessibility settings to respect the system's set font size when displaying web pages (Android). This is also the last version to support Android Ice Cream Sandwich.
Firefox 56 was released on September 28, 2017 for both desktop and Android. Among the many additions are: a new layout for the "Preferences" page, the launch of Firefox Screenshots, support for address form autofill, hardware acceleration for AES-GCM, update of the Safe Browsing protocol to version 4, and improved security or verifying update downloads (desktop), and improvement of support for WebExtensions, and the end of support for Adobe Flash (Android). Starting with this version, Android support is exclusively for Android Jelly Bean and above.
Firefox 57 was released on November 14, 2017 for desktop and Android with the name Firefox Quantum.ZDNet dubbed it a "comeback" following years of falling market share against Google Chrome. The release included a new interface design, codenamed "Photon", and a new rendering engine almost twice as fast as the previous one used. One of the largest visual changes in Photon was the removal of the search box from the address bar. Firefox 57 no longer supports legacy add-ons using XUL technologies. That same day, Mozilla announced that Google would be the default search engine in the USA and Canada, a departure from Yahoo, which had been the default search engine in the USA and Canada since 2014.
Firefox 58 was released on January 23, 2018 for desktop and Android. Among the additions were: support for credit card autofill, the drop of support for user profiles in previous versions of Firefox, a warning to alert users and site owners of planned security changes to sites affected by the gradual distrust plan for the Symantec certificate authority (desktop), full screen bookmark management with folder support, support for FLAC (Free Lossless Audio Codec) playback, ability to change the status bar color in themes, and removal of the Firefox Search widget from home screen (Android).
Firefox 59 was released on March 13, 2018 for desktop and Android. Among the additions were: faster load times and improved graphics, improved Real-Time Communications (RTC) capabilities, additional features for Firefox Screenshots, support for W3C specs for pointer events, and Private Browsing Mode's removal of path information from referrers to prevent cross-site tracking (desktop), and the addition of Firefox as an Assist app, support for HLS (HTTP Live Streaming) playback for improved compatibility with video sites, and removal of the "about:" page.
Added support for WebAssembly, an emerging standard that brings near-native performance to Web-based games, apps, and software libraries without the use of plugins.
Added automatic captive portal detection, for easier access to Wi-Fi hotspots. When accessing the Internet via a captive portal, Firefox will alert users and open the portal login page in a new tab.
Enabled multi-process Firefox for Windows users with touch screens
Added user warnings for non-secure HTTP pages with logins. Firefox now displays a “This connection is not secure” message when users click into the username and password fields on pages that don’t use HTTPS.
Implemented the Strict Secure Cookies specification which forbids insecure HTTP sites from setting cookies with the "secure" attribute. In some cases, this will prevent an insecure site from setting a cookie with the same name as an existing "secure" cookie from the same base domain.
Enhanced Sync to allow users to send and open tabs from one device to another.
Improved text input for third-party keyboard layouts on Windows. This will address some keyboard layouts that:
have chained dead keys.
input two or more characters with a non-printable key or a dead key sequence.
input a character even when a dead key sequence failed to compose a character.
Removed support for Netscape Plugin API (NPAPI) plugins other than Flash. Silverlight, Java, Acrobat and the like are no longer supported.
Removed Battery Status API to reduce fingerprinting of users by trackers.
Improved experience for downloads:
Notification in the toolbar when a download fails.
Quick access to five most recent downloads rather than three.
Larger buttons for canceling and restarting downloads.
Displaying (but allowing users to override) an “Untrusted Connection” error when encountering SHA-1 certificates that chain up to a root certificate included in Mozilla’s CA Certificate Program. (Note: Firefox continues to permit SHA-1 certificates that chain to manually imported root certificates.)
Migrated Firefox users on Windows XP and Windows Vista operating systems to the extended support release (ESR) version of Firefox.
When not using Direct2D on Windows, Skia is used for content rendering.
Enabled CSS Grid Layout, opening up a world of new possibilities for graphic design.
Redesigned Responsive Design Mode to include device selection, network throttling, and more.
Improved security for screen sharing, which now shows a preview and no longer requires a whitelisted domain.
Reduced APK file size by more than 5 MB for faster download and installation.
Display of media controls to pause or resume playback on the Android notification bar. This gives users easy access to controls and allows them to see when audio or video is playing (and consuming mobile data) on Firefox.
Launched Windows support for WebVR, bringing immersive experiences to the web.
Added options that let users optimize recent performance improvements
Setting to enable Hardware VP9 acceleration on Windows 10 Anniversary Update for better battery life and lower CPU usage while watching videos
Setting to modify the number of concurrent content processes for faster page loading and more responsive tab switching
Simplified installation process with a streamlined Windows stub installer
Firefox for Windows 64-bit is now installed by default on 64-bit systems with at least 2GB of RAM
Full installers with advanced installation options are still available
Improved address bar functionality
Search with any installed one-click search engine directly from the address bar
Search suggestions appear by default
When entering a hostname (like pinterest.com) in the URL bar, Firefox resolves to the secure version of the site (https://www.pinterest.com) instead of the insecure version (http://www.pinterest.com) when possible
Updated Sidebar for bookmarks, history, and synced tabs so it can appear at the right edge of the window as well as the left
Added support for stereo microphones with WebRTC
Simplified printing from Reader Mode
Updated Firefox for OS X and macOS to allow users to assign custom keyboard shortcuts to Firefox menu items via System Preferences
Browsing sessions with a high number of tabs are now restored in an instant
Make screenshots of webpages, and save them locally or upload them to the cloud. This feature will undergo A/B testing and will not be visible for some users.
Added Belarusian (be) locale
Various security fixes
Modernized application update UI to be less intrusive and more aligned with the rest of the browser. Only users who have not restarted their browser 8 days after downloading an update or users who opted out of automatic updates will see this change.
Made the Adobe Flash plugin click-to-activate by default and allowed only on http:// and https:// URL schemes. (This change will not be visible to all users immediately.)
Firefox does not support downgrades, even though this may have worked in past versions. Users who install Firefox 55+ and later downgrade to an earlier version may experience issues with Firefox.
Sites that don’t use SSL can no longer access Geolocation APIs to determine a user’s physical location
A completely new browsing engine, designed to take full advantage of the processing power in modern devices
A redesigned interface with optimizations for touch screens
A unified address and search bar. New installs will see this unified bar
A revamped new tab page that includes top visited sites, recently visited pages, and recommendations from Pocket (in the US, Canada, and Germany)
An updated product tour to orient new and returning Firefox users
AMD VP9 hardware video decoder support for improved video playback with lower power consumption
An expanded section in preferences to manage all website permissions
Various security fixes
Firefox now exclusively supports extensions built using the WebExtension API, and unsupported legacy extensions will no longer work
The browser's autoscroll feature, as well as scrolling by keyboard input and touch-dragging of scrollbars, now use asynchronous scrolling. These scrolling methods are now similar to other input methods like mousewheel, and provide a smoother scrolling experience
The content process now has a stricter security sandbox that blocks filesystem reading and writing on Linux, similar to the protections for Windows and macOS that shipped in Firefox 56
Middle mouse paste in the content area no longer navigates to URLs by default on Unix systems
Removed the toolbar Share button
Some older versions of the ATOK IME, including ATOK 2006, 2008, 2009 and 2010, can cause crashes and are therefore disabled on the Windows 64-bit version of Firefox Quantum
The default font for Japanese text is now Meiryo
A complete visual refresh of both the Light and Dark DevTools themes, matching the new visual style of Firefox Quantum
The Inspector shows the values of CSS variables on hover
Completely new and re-designed Console panel. Joining the Debugger and the Network Monitor, the Console has been rewritten using modern web technologies such as React and Redux. It now also allows to inspect objects in context.
Performance improvements for faster page loading and stability
Updated interface, including a revamped new tab page that includes top visited sites, recently visited pages, and recommendations from Pocket (in the US, Canada and Germany)
Video decoding is shut down when the tab playing the media is sent to the background. Video resumes when the tab is brought to the foreground. Audio will not be affected
Added an option to enable tracking protection outside of private browsing
Automatically enabled private mode on compatible keyboards during private browsing
Long URLs in the URL bar are now scrollable
Added Wolof (wo) locale
Firefox for Android now exclusively supports extensions built using the WebExtension API, and unsupported legacy extensions will no longer work
Android Apps can now launch Firefox Custom Tabs
November 29, 2017
Off-cycle security and stability update.
Fix for a video color distortion issue on YouTube and other video sites with some AMD devices.
Fix for an issue with prefs.js when the profile path has non-ASCII characters.
Various security fixes.
Fixed an issue in which Google map crashes on macOS with Intel HD Graphics 3000.
Blocked injection of a client library associated with the RealPlayer Free player which is known to cause performance problems in Firefox.
Fixed an issue in which Stop button no longer appears immediately after starting a navigation.
Rendering graphics for Windows users by using Off-Main-Thread Painting (OMTP)
Improvements to Firefox Screenshots:
Copy and paste screenshots directly to your clipboard
Firefox Screenshots now works in Private Browsing mode
Added support for credit card autofill
Added Nepali (ne-NP) locale
Users can enable Tracking Protection at all times.
Fonts installed in non-standard directories will no longer appear blank for Linux users
Various security fixes
User profiles created in Firefox 58 (and in future releases) are not supported in previous versions of Firefox. Users who downgrade to a previous version should create a new profile for that version.
Added a warning to alert users and site owners of planned security changes to sites affected by the gradual distrust plan for the Symantec certificate authority
Implemented the PerformanceNavigationTiming API
Added PerformanceResourceTiming.workerStart so sites can measure service worker startup time
Performance improvements, including:
Support for Progressive Web Apps
Added ability to Sync only over non-metered connections (e.g., WiFi). Setting available via Sync Preferences.
Added full screen bookmark management with folder support
Added support for FLAC (Free Lossless Audio Codec) playback
Added ability to change the status bar color in themes
Added Bengali from Bangladesh (bn-BD) and Nepali (ne-NP) locales
Removed the Firefox Search widget from home screen
Updated the Safe Browsing protocol to version 4
January 29, 2018
Off-cycle security and stability update.
Fixed an issue in which, when using certain non-default security policies on Windows (for example with Windows Defender Exploit Protection or Webroot security products), Firefox 58.0 would fail to load pages.
Fixed performance issue whereby some installations were initially slow to load pages.
Implemented RTP Transceiver to give pages more fine grained control over calls
Implemented features to support large scale conferences
Added support for W3C specs for pointer events and improved platform integration with added device support for mouse, pen, and touch screen pointer input
Added the Ecosia search engine as an option for German Firefox
Added the Qwant search engine as an option for French Firefox
Added settings in about:preferences to stop websites from asking to send notifications or access your device’s camera, microphone, and location, while still allowing trusted websites to use these features
Various security fixes
Firefox Private Browsing Mode will remove path information from referrers to prevent cross-site tracking
Added Firefox as an Assist App so users can start a search by long-pressing the home button
Added support for HLS (HTTP Live Streaming) playback for improved compatibility with video sites
Firefox Private Browsing Mode will remove path information from referrers sent to third parties to help prevent third-party data leakage
Off-cycle security and stability update.
Fixed invalid page rendering with hardware acceleration enabled
Fixed an issue in which Windows 7 users with touch screens or certain 3rd party desktop applications which interact with Firefox through accessibility services may experience random browser crashes
Fixed an issue in which browser keyboard shortcuts (eg copy Ctrl+C) don't work on sites that use those keys with resistFingerprinting enabled
Fixed high CPU / memory churn caused by third-party software on some computers.
Fixed an issue in which users who have configured an "automatic proxy configuration URL" and want to reload their proxy settings from the URL will find the Reload button disabled in the Connection Settings dialog when they select Preferences/Options > Network Proxy > Settings
Fixed an issue in which URL fragment identifiers break Service Worker responses.
Fixed an issue in which users trying to cancel a print around the time it completed would continue to get intermittent crashes
Fixed broken getUserMedia (audio) on DragonFly, FreeBSD, NetBSD, OpenBSD. Video chat apps either wouldn't work or be always muted
Various security fixes
Fixed top crasher on Firefox for Android
Fixed an issue in which URL fragment identifiers break Service Worker responses
Firefox 60 and Firefox 60 ESR were released on May 9, 2018 for desktop (both) and Android (no ESR). It includes a policy engine that allows customized Firefox deployments in enterprise environments, using Windows Group Policy or a cross-platform JSON file, enhancements to New Tab / Firefox Home, redesigned Cookies and Site Storage section in Preferences for greater clarity and control of first- and third-party cookies, the application of Quantum CSS to render browser UI, support for Web Authentication API, which allows USB tokens for website authentication, an option for Linux users to show or hide page titles in a bar at the top of the browser, improved WebRTC audio performance and playback for Linux users (desktop), exclusive support for extensions built using the WebExtension API (ESR), the implementation of Quantum CSS (also known as Stylo) in Android for faster page rendering; and the addition of View Page Source option to the Page Action menu (Android).
Firefox 61 was released on June 26, 2018 for both desktop and Android. Among the many additions were: Improvements for dark theme support across the entire Firefox user interface, added support to allow WebExtensions to hide tabs, improved bookmark syncing, convenient access to more search engines (desktop), improved security and enhanced performances (both), and the fix for a recurring crash on Samsung Galaxy S8 devices running Android Oreo (Android).
Firefox 62 was released on September 5, 2018 for both desktop and Android. Among the many additions were: FreeBSD support for WebAuthn, a preference that allows users to distrust certificates issued by Symantec in advance of removing all trust for Symantec-issued certificates in Firefox 63, improved graphics rendering for Windows users without accelerated hardware using Parallel-Off-Main-Thread Painting, CSS Variable Fonts (OpenType Font Variations) support, and support for CSS Shapes, allowing for richer web page layouts (desktop), and improved scrolling performance, faster page load times over WiFi connections by loading from the network cache if disk cache is slow, and “Product and feature tips” toggle in Notifications settings (Android).
Firefox 63 was released on October 23, 2018 for both desktop and Android. Among the many additions and changes were: Performance and visual improvements for Windows and macOS users, content blocking, WebExtensions running in their own process in Linux, recognition of the operating system accessibility setting for reducing animation, the addition of Amazon and Google as Top Sites tiles on the Firefox Home (New Tab) page, the removal of the "Never Check for Updates" option from "about:preferences" and "Open in Sidebars" feature from the Library (desktop), support for Picture-In-Picture video, and use of notification channels (Android).
Firefox 64 version 64.0 was released on December 11, 2018 for desktop only. Firefox 64 for desktop provides better recommendations, enhanced tab management, easier performance management, improved performance for Mac and Linux users, by enabling link time optimization (Clang LTO), more seamless sharing on Windows, the option to remove add-ons using the context menu on their toolbar buttons, TLS certificates issued by Symantec that are no longer trusted by Firefox, and the availability of WebVR on macOS. Three days later, version 64.0.1 was released for Android only. Firefox 64 for Android provides faster and more responsive scrolling and fixes for performance lags for users with installed password manager apps and an issue that resulted in the loading indicator using too much CPU and power.
Firefox 65 was released on January 29, 2019 for both desktop and Android. Among the many additions and changes were: improved performance and web compatibility, with support for the WebP image format; enhanced security for macOS, Linux, and Android users via stronger stack smashing protection which is now enabled by default for all platforms (both desktop and Android); enhanced tracking protection; updated language settings in Preferences; support for Handoff on macOS; better video streaming experience for Windows users; easier performance management; improved pop-up blocker; the availability of Firefox for Windows with 32- and 64-bit MSI installers for easier enterprise deployments; additional support for Flexbox (desktop); and the restoration of Chromecast controls to the location bar (Android).
Firefox 66 was released on March 19, 2019 for both desktop and Android. Among the many additions and changes were: Prevention of websites from automatically playing sound, smoother scrolling (both), improved search experience and performance and better user experience for extensions, the addition of basic support for macOS Touch Bar and of support for Windows Hello on Windows 10, the enabling of AV1 support on 32-bit Windows and MacOS (desktop), and the addition of support to open files from external storage, such as an SD card (Android).
Firefox 67 was released on May 21, 2019 for both desktop and Android. Among the many additions and changes were: Lowering priority of setTimeout during page load; suspending unused tabs; the ability to block known cryptominers and fingerprinters in the Custom settings of the Content Blocking preferences; improvement of keyboard accessibility; usability and security improvements in Private Browsing; protection against running older versions of the browser which can lead to data corruption and stability issues (desktop); new Firefox search widget with voice input; and removal of the Guest Session feature to streamline user experience (Android).
Official Firefox 60.0 Extended Support Release (ESR).
Firefox Quantum arrives in the ESR channel. Key features include:
A completely new browser engine, designed to take full advantage of the processing power in modern devices
A redesigned interface with a clean, modern appearance, consistent visual elements, and optimizations for touch screens
A unified address and search bar. New installs will see this unified bar.
A revamped new tab page that includes top visited sites, recently visited pages, and recommendations from Pocket (in the US, Canada, and Germany)
An updated product tour to orient new and returning Firefox users
Support for enterprise environments, with a policy engine that allows customized Firefox deployments using Windows Group Policy or a cross-platform JSON file
Firefox now exclusively supports extensions built using the WebExtension API. Unsupported legacy extensions will no longer work in Firefox 60 ESR, but they will continue to work in Firefox 52 ESR, which will be supported until September 2018.
DNS over HTTPS (DOH) functionality available.
TLS certificates issued by Symantec before June 1st, 2016 are no longer trusted by Firefox. The "security.pki.distrust_ca_policy" preference can be set to 0 to reinstate trust in those certificates
Faster page rendering with Quantum CSS improvements and the new retained display list feature
Faster switching between tabs on Windows and Linux
WebExtensions now run in their own process on MacOS
Convenient access to more search engines: You can now add search engines to the address bar “Search with” tool from the page action menu when on a webpage that provides an OpenSearch plugin
Share links from Firefox for MacOS more easily: You can now share the URL of an active tab from the page actions menu in the address bar
On-by-default support for the latest draft of the TLS 1.3 specification
Access to FTP subresources inside http(s) pages has been blocked
A more consistent user experience: Improvements for dark theme support across the entire Firefox user interface
More customization for tab management: added support to allow WebExtensions to hide tabs
Improved bookmark syncing
The settings for customizing your homepage and new tab page in Firefox have been added to a new Preferences section that can be accessed from Firefox at about:preferences#home. The settings can also be accessed via the gear icon on the New Tab page.
Quantum CSS improvements which improve page rendering times
Faster scrolling due to treating touch event listeners as passive by default
Improved security: On-by-default support for the latest draft of the TLS 1.3 specification
Fixed a recurring crash on Samsung Galaxy S8 devices running Android Oreo (8.0)
Firefox 68 and Firefox 68 ESR were released on July 9, 2019 for desktop (both) and Android (no ESR). Among the many additions were: Expansion of Dark Mode in Reader view, new reporting feature in about:addons, cryptomining and fingering protections, WebRender for Windows 10, Windows Background Intelligent Transfer Service (BITS) update download support (desktop), user and enterprise added certificates read from the OS by default (68 ESR), improved web page painting performance by avoiding redundant calculations during paint, and introduction of WebAuthn (the Web Authentication API; Android).
Mozilla made Firefox for 64-bit Linux a priority with the release of Firefox 4, labeling it as tier 1 priority. Since being labeled tier 1, Mozilla has been providing official 64-bit releases for its browser for Linux. Vendor-backed 64-bit support has existed for Linux distributions such as Novell/SUSE Linux, Red Hat Enterprise Linux, and Ubuntu prior to Mozilla's 64-bit support, even though vendors were faced with the challenge of having to turn off the 64-bit JIT compiler due to its instability prior to Firefox 4.
The official releases of Firefox for macOS are universal builds that include both 32-bit and 64-bit versions of the browser in one package, and have been this way since Firefox 4. A typical browsing session uses a combination of the 64-bit browser process and a 32-bit plugin process, because some popular plugins still are 32-bit. As of April 19, 2017, Firefox 53 has dropped support for 32-bit macOS.
The 32-bit and 64-bit versions of Windows can be used to run 32-bit Firefox. In late 2012, Mozilla announced 64-bit Windows builds would be stopped but later reversed the decision. As of April 2015[update], 64-bit Windows builds are available as 38.0 Beta and newer. 64-bit builds for Windows are officially supported as of November 2015 with the release of Firefox 42. All NPAPI plugins except Adobe Flash Player are blacklisted and unsupported on both 32-bit and 64-bit versions.
Other CPU architectures
Besides x86, Firefox also supported other CPU architectures including ARMv7, SPARC, PowerPC, and 68k on different tiers. Mozilla terminated support for PowerPC-based Macintosh computers with Firefox 3.6, but a third-party project known as TenFourFox ported several newer versions of Firefox, the latest being based on Firefox 45 ESR.
Firefox for iOS is not listed in this table as its version numbers would be misleading; it uses version numbers that do not correspond to any of the other Firefox versions. Those share a core component, the Gecko rendering engine, and track its version numbers, whereas the version for the iOS operating system uses the operating system's rendering engine (WebKit), rather than Mozilla's (Gecko).
^Class 09: Computer software for use in managed communications and connectivity.
Class 42: Computer consultancy services; licensing and rental of computer software; design and development of computer software; maintenance, installation and up-dating of computer software; advisory services relating to computer programs and software