User:Rukario-sama/sandbox

Mozilla 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 66 is the latest version released on March 19, 2019.

Current supported official releases

 * Firefox 66.0.3
 * Firefox 60.6.1 ESR

Current supported test releases

 * Firefox 67.0 Beta
 * Firefox 67.0 Developer Edition
 * Firefox 68.0 Nightly

Future official releases

 * Rapid
 * Firefox 67.0
 * Firefox 68.0
 * Firefox 69.0
 * Firefox 70.0
 * Firefox 71.0


 * ESR
 * Firefox 60.7 ESR
 * Firefox 60.8 ESR
 * Firefox 60.9 ESR
 * Firefox 68.0 ESR
 * Firefox 68.1 ESR
 * Firefox 68.2 ESR
 * Firefox 68.3 ESR

Future test releases

 * Firefox 68.0 Developer Edition
 * Firefox 68.0 Beta
 * Firefox 69.0 Nightly
 * Firefox 69.0 Developer Edition
 * Firefox 69.0 Beta
 * Firefox 70.0 Nightly
 * Firefox 70.0 Developer Edition
 * Firefox 70.0 Beta
 * Firefox 71.0 Nightly
 * Firefox 71.0 Developer Edition
 * Firefox 71.0 Beta
 * Firefox 72.0 Nightly
 * Firefox 72.0 Developer Edition
 * Firefox 72.0 Beta
 * Firefox 73.0 Nightly

Early versions
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 XUL user 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 Gecko layout 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
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 WYSIWYG HTML 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.

Firefox
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.

Firefox 1.5


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 1.5.0.12 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.

Firefox 2


On October 24, 2006, Mozilla released Firefox 2. This version included updates to the tabbed browsing environment, the extensions manager, the GUI (Graphical User Interface), and the find, search and software update engines. It also implemented a new session restore feature, inline spell checking, and an anti-phishing feature which was implemented by Google as an extension and later merged into the program itself.

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 2.0.0.20 was the final version that could run under an unmodified installation of Windows NT 4.0, Windows 98, and Windows ME. Subsequently, Mozilla Corporation announced it would not develop new versions of Firefox 2 after the 2.0.0.20 release, but continued Firefox 2 development as long as other programs, such as Thunderbird mail client, depended on it. The final internal release was 2.0.0.22, released in late April 2009.

Firefox 3


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. Tabbed browsing was more popularised in this version. The final version under 3.0 is Firefox 3.0.19.

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.

Firefox 3.5


Version 3.5, codenamed Shiretoko, adds a variety of new features to Firefox. Initially numbered Firefox 3.1, Mozilla developers decided to change the numbering of the release to 3.5 in order to reflect a significantly greater scope of changes than originally planned. The final release was on June 30, 2009. The changes included much faster performance thanks to an upgrade to SpiderMonkey JavaScript engine called TraceMonkey and rendering improvements, and support for the  and   tags as defined in the HTML5 specification, with a goal to offer video playback without being encumbered by patent problems associated with many video technologies. Cross-site XMLHttpRequests (XHR), which can allow for more powerful web applications and an easier way to implement mashups, are also implemented in 3.5. A new global JSON object contains native functions to efficiently and safely serialize and deserialize JSON objects, as specified by the ECMAScript 3.1 draft. Full CSS 3 selector support has been added. Firefox 3.5 uses the Gecko 1.9.1 engine, which includes a few features that were not included in the 3.0 release. Multi-touch trackpad support was also added to the release, including gesture support like pinching for zooming and swiping for back and forward. Firefox 3.5 also features an updated logo.

Firefox 3.6
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.

Support for Firefox 3.6 ended on April 24, 2012.

Firefox 4


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.

Firefox 4 was released on March 22, 2011, originally Firefox 3.7 (Gecko 1.9.3) during its alpha stage, brought a new user interface and is said to be faster. Early mockups of the new interface on Windows, Mac OS X, and Linux were first made available in July 2009. Other new features included improved notifications, tab groups, application tabs, a redesigned add-on manager, integration with Firefox Sync, and support for multi-touch displays.

Firefox 4 was based on the Gecko 2.0 engine, which added or improved support for HTML5, CSS3, WebM, and WebGL. It also included a new JavaScript engine (JägerMonkey) and better XPCOM APIs.

Firefox 5 through 9
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.

New releases are planned to occur at six-week intervals. 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 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. Version 5 significantly improved the speed of web-related tasks, such as loading pages with combo boxes or MathML. Mozilla also integrated the HTML5 video WebM standard into the browser, allowing playback of WebM video.

Firefox 6 released on August 16, 2011, introducing permissions manager, new address bar highlighting (the domain name is black while the rest of the URL is gray ), streamlining the look of the site identity block, quicker startup time, a ScratchPad JavaScript compiler, and many other new features. This update also brought the infamous feature that JavaScript entered in the address bar does not run.

Firefox 7 released 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. Mozilla 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 9 released on December 20, 2011 and 9.0.1 a day later, includes various new features such as Type Inference, which boosts JavaScript performance up to 30%, 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 font-stretch, improved support for text-overflow, improved standards support for HTML5, MathML, and CSS, and fixed several security problems. It also features a large list of bug fixes.

Firefox 10 through 16
Firefox 10 and Firefox ESR 10 were released on January 31, 2012. Firefox 10 ESR is the first Extended Support Release (ESR) as previosuly in January 10, 2012, where the Mozilla Foundation announced the availability of an ESR version of Firefox. Firefox 10 hides the forward arrow button until there is a website to go forward to, or it is manually activated. Firefox 10 adds a Full Screen API and improved WebGL performance. 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 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-on Sync, 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 1.4.0 for Android was released on June 26, 2012, 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 Firefox 14.0.1 for mobile and desktop on July 17, 2012, instead of Firefox 14.0 for the desktop and Firefox 14.0.1 for mobile clients.

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 was released on August 28, 2012. This version includes a "Responsive Design View" developer tool, adds support for the Opus audio format, and adds preliminary native PDF support (disabled by default).

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. Version 16.0.2 was released October 26, 2012. It fixed additional security issues, and is also the final release to support Mac OS X Leopard.

Firefox 17 through 23
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.

Starting with Firefox 17, Mac OS X support is exclusively for Snow Leopard, Lion, and Mountain Lion.

Firefox 18 was released on January 8, 2013. A new feature for Firefox 18 is IonMonkey, Mozilla's next generation JavaScript engine, it also uses some functions of WebRTC.

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  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. Partial CSS Flexbox support added (flex-wrap support is currently scheduled for Firefox 28 ). A new feature for Firefox 22 was OdinMonkey, Mozilla's next generation JavaScript engine.

Firefox 23 was released on August 6, 2013. It includes an updated Firefox logo, mixed content blocking enabled by default to defend against man-in-the-middle attacks, implementation of the  form control attribute in HTML5, dropping support for the   HTML element as well as   CSS element, the restriction to have to "switch to a different search provider across the entire browser", and a global browser console, a new network monitor among other things. JavaScript is automatically enabled by the update, without regard to the previous setting, and the ability to turn it off has been removed from the interface; the "contentious" change was made because many websites depend on JavaScript and it was felt that users unaware that they had disabled JavaScript were attributing the resulting unpredictable layout to software bugs in Firefox.

Firefox 24 through 30
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  attribute,   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 through 37
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.

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.

Firefox 38 through 44
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 through 51
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 46 was released on April 26, 2016 for both desktop and Android. Among the many additions were improved security of the JavaScript Just In Time (JIT) Compiler, the GTK3 integration (Linux only), HKDF support for Web Crypto API, and removal of support for Android 3.0 (Android only).

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 48 is the last Firefox version to support Mac OS X Snow Leopard, Mac OS X Lion, and OS X Mountain Lion. Additionally, support for old processors without SSE2 extensions such as the AMD Athlon XP and Pentium III was dropped.

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 through 59
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.

Firefox 60 through 67
Firefox 60 and Firefox 60 ESR were released on May 9, 2018 for desktop (both) and Android (no ESR). 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 was released on December 11, 2018 for desktop only. Among the many additions and changes were: 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, Firefox 64.0.1 was released for Android only. Among the many additions and changes were: 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).

x86 family
Native 64-bit builds are officially supported on Linux, macOS, and Windows (since version 42).

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. , 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.