Firefox version history

Firefox was created by Dave Hyatt and Blake Ross as an experimental branch of the Mozilla browser, first released as Firefox 1.0 on November 9, 2004. Starting with version 5.0, a rapid release cycle was put into effect, resulting in a new major version release every six weeks. This was gradually accelerated further in late 2019, so that new major releases occur on four-week cycles starting in 2020.

Rapid releases
In March 2011, Mozilla presented plans to switch to a faster 16-week development cycle, similar to Google Chrome. Ars Technica noted that this new cycle entailed "significant technical and operational challenges" for Mozilla (notably preserving third-party add-on compatibility), but that it would help accelerate Firefox's adoption of new web standards, feature, and performance improvements. This plan was implemented in April 2011. The release process was split into four "channels", with major releases trickling down to the next channel every six to eight weeks. For example, the nightly channel would feature a preliminary unstable version of Firefox 6, which would move to the experimental "Aurora" channel after preliminary testing, then to the more stable "beta" channel, before finally reaching the public release channel, with each stage taking around six weeks. For corporations, Mozilla introduced an Extended Support Release channel, with new versions released every 30 weeks (and supported for 12 more weeks after a new ESR version is released), though Mozilla warned that it would be less secure than the release channel, since security patches would only be backported for high-impact vulnerabilities.

In 2017, Mozilla abandoned the Aurora channel, which saw low uptake, and rebased Firefox Developer Edition onto the beta channel. Mozilla uses A/B testing and a staged rollout mechanism for the release channel, where updates are first presented to a small fraction of users, with Mozilla monitoring its telemetry for increased crashes or other issues before the update is made available to all users. In 2020, Firefox moved to a four-week release cycle, to catch up with Chrome in support for new web features. Chrome switched to a four-week cycle a year later.

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 HTML video WebM standard into the browser, allowing playback of WebM videos.

Firefox 6 was released on August 16, 2011, introducing a 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, a quicker startup time, a ScratchPad JavaScript compiler, and many other new features. This update also brought the infamous feature that caused JavaScript entered in the address bar to not run.

Firefox 7 was released on September 27, 2011, and 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 to fix 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 was released on November 8, 2011 and 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. Added option in preferences to lazy load session tabs (prior to that it could be switched by config setting since version 4.0 beta 7 ).

Firefox 9 was released on December 20, 2011, 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 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 on 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,, 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 a 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 was released on June 26, 2012, for mobile devices only, just outside the regular release schedule of the web browser. In order to sync the version numbers of the desktop and mobile versions 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 mobile devices.

Firefox 14 introduces a new hang detector (similar to how Mozilla currently collects other data) that allows Mozilla to collect, analyze, and identify the cause of the browser freezing/hanging. Mozilla uses 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, with 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 were 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.

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, and introduced a panel-based download manager, along with H.264 decoding on the  tag (on Windows only), and per-window private browsing. 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, and an 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 was added (flex-wrap support was 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 the   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, a separate find bar for each tab and many other bug fixes.

Firefox 26 was released on 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 after having been tested through a toggle in  since version 24, released on September 17, 2013. Also, it brings many bug fixes, security improvements, and developer-related changes. Firefox 28 was released on March 18, 2014, and added support for VP9 video decoding and support for Opus in WebM.

Firefox 29 was released on April 29, 2014, and includes a redesigned interface codenamed Australis, it also removes the add-on bar and moves its content to the navigation bar. Additionally, it introduced automatic correction of protocol typos to the address bar, meaning that, for example,  is automatically corrected to. 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 would 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 also includes security fixes. Firefox 36 was released for desktop on February 24, 2015, bringing full HTTP/2 support and other smaller improvements and fixes.

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, 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. 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. 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. 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. Major changes included the availability of a 64-bit version for Windows 7 and above, and a new strict blocklist.

Firefox 44 was released on January 26, 2016. 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, and support for the brotli compression format via HTTPS content-encoding. The "Ask me every time" cookies option was additionally removed without any notifications.

Firefox 45 through 51
Firefox 45 and Firefox 45 ESR were released on March 8, 2016. 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 the Tab Groups (panorama) feature.

Firefox 46 was released on April 26, 2016. 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.

Firefox 47 was released on June 7, 2016. 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 HTML video, enabling VP9 video codec for users with fast machines, the ability of embedded YouTube videos to play with HTML video if Flash is not installed, and the addition of the Latgalian language.

Firefox 48 was released on August 2, 2016. Among the many additions were enhanced download protection and the removal of the 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. It is the last Firefox version to support Mac OS X Snow Leopard, Mac OS X Lion, and OS X Mountain Lion.

Firefox 49 was released on September 20, 2016. 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 HTML 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. Additionally, support for processors without SSE2 extensions such as the AMD Athlon XP and Pentium III under Windows is dropped.

Firefox 50 was released on November 15, 2016. 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, Mac OS, and Linux, and increased availability of WebGL to more than 98 percent of users on Windows 7 and newer.

Firefox 51 was released on January 24, 2017. 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. An important aspect of Firefox ESR 52.0 is that it is the first ESR version based on the 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, and user warnings for insecure HTTP pages with logins. 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. Starting with Firefox 53, Microsoft Windows support is exclusively for Windows 7 and above. Other major changes included improved graphics stability for Windows users with the addition of compositor process separation, the addition of light and dark "compact" themes based on the themes included with Firefox Developer Edition, the removal of support for 32-bit macOS and Linux for processors older than the Pentium 4 and Opteron processors, a new visual design for audio and video controls, support for WebM video with alpha compositing, which allows playing videos with transparent backgrounds, and support for displaying estimated reading time for pages in Reader Mode.

Firefox 54 was released on June 13, 2017. Major changes included simplifying the download button and download status panel, support for multiple content processes, the ability to create and save custom devices in responsive web design mode, and improved audio and video playback in the browser.

Firefox 55 was released on August 8, 2017. Major changes included the launch of Windows support for WebVR, options that let users optimize recent performance improvements, simplification of the installation process with a streamlined Windows stub installer, improvements to address bar functionality, and simplified printing from Reader Mode.

Firefox 56 was released on September 28, 2017. 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, improved security or verifying update downloads, and improved support for WebExtensions. Another change was the introduction of the mozlz4 format, a proprietary variant of the lz4 compression format (.mozlz4 and .jsonlz4 file extensions instead of .json.lz4 as per unix/linux standard). Session data is stored in the lz4 format instead of plain text. Firefox 56 cannot recognize the legacy plain text session files, only the lz4-encoded ones.

Firefox 57 was released on November 14, 2017, 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 US and Canada, a departure from Yahoo, which had been the default search engine in the US and Canada since 2014.

Firefox 58 was released on January 23, 2018. 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, full screen bookmark management with folder support, support for FLAC (Free Lossless Audio Codec) playback, and the ability to change the status bar color in themes.

Firefox 59 was released on March 13, 2018. 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, Private Browsing Mode's removal of path information from referrers to prevent cross-site tracking, and the addition of Firefox as an Assist app, and support for HLS (HTTP Live Streaming) playback for improved compatibility with video sites.

Firefox 60 through 67
Firefox 60 and Firefox 60 ESR were released on May 9, 2018. 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, a 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, and exclusive support for extensions built using the WebExtension API (ESR).

Firefox 61 was released on June 26, 2018. 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, improved security and enhanced performance.

Firefox 62 was released on September 5, 2018. 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, support for CSS Shapes, allowing for richer web page layouts, improved scrolling performance, and faster page load times over Wi-Fi connections by loading from the network cache if disk cache is slow. The bookmarks' Description field was deprecated and will be removed completely in future releases.

Firefox 63 was released on October 23, 2018. 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, and the removal of the "Never Check for Updates" option from "about:preferences" and the "Open in Sidebars" feature from the Library.

Firefox 64 version 64.0 was released on December 11, 2018. 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.

Firefox 65 was released on January 29, 2019. 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, a better video streaming experience for Windows users, easier performance management, an improved pop-up blocker, the availability of Firefox for Windows with 32- and 64-bit MSI installers for easier enterprise deployments, and additional support for Flexbox.

Firefox 66 was released on March 19, 2019. Among the many additions and changes were: Prevention of websites from automatically playing sound, smoother scrolling (both), an 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, along with the enabling of AV1 support on 32-bit Windows and macOS.

Firefox 67 was released on May 21, 2019. Major changes included lowering priority of setTimeout during page load, suspending (unloading) unused tabs to clear memory, the ability to block known cryptominers and fingerprinters in the Custom settings of the Content Blocking preferences, improvements to keyboard accessibility, usability and security improvements in Private Browsing, and protection against running older versions of the browser which can lead to data corruption and stability issues.

Firefox 68 through 77
Firefox 68 and Firefox 68 ESR were released on July 9, 2019. Among the many additions were: Expansion of Dark Mode in Reader view, a new reporting feature in about:addons, cryptomining and fingerprinting protections, WebRender for Windows 10, Windows Background Intelligent Transfer Service (BITS) update download support, 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).

Firefox 69 was released on September 3, 2019. Among the additions were: Enhanced Tracking Protection, the Block Autoplay feature, support for the Web Authentication HmacSecret extension via Windows Hello for versions of Windows 10 May 2019 or newer, support for receiving multiple video codecs, JIT support for ARM64, and improvements for download UI, performance (Windows 10), and battery life (macOS).



Firefox 70 was released on October 22, 2019. Among the additions were: more privacy protection from Enhanced Tracking Protection, more security protection from Firefox Lockwise, improvements to core engine components for better browsing on more sites, a stand-alone Firefox account menu for easy access to Firefox services like Monitor and Send, the dark mode preference for built-in Firefox pages, and inactive CSS.

Firefox 71 was released on December 3, 2019. Among the additions were: improvements to the integrated password manager Lockwise, more information about Enhanced Tracking Protection in action, picture-in-picture for Windows, and native MP3 decoding on Windows, Linux, and macOS.

Firefox 72 was released on January 7, 2020. Among the additions were: the replacement of notification request pop-ups, the ETP blocking fingerprinting scripts by default, the availability of picture-in-picture video for macOS and Linux, and the removal of support for blocking images from individual domains because of low usage and poor user experience.

Firefox 73 was released on February 11, 2020. Among the additions were: a new global default zoom level setting, a "readability backplate" solution which places a block of background color between the text and background image, improved audio quality when playing back audio at a faster or slower speed, a prompt to save logins if a field in a login form was modified, and rolling out WebRender to laptops with Nvidia graphics cards with drivers newer than 432.00, and screen sizes smaller than 1920x1200.

Firefox 74 was released on March 10, 2020. Additions included: improvement of login management with the ability to reverse alpha sort (Name Z-A) in Lockwise, simple importing of bookmarks and history from Microsoft Edge on Windows and Mac, use of Add-ons Manager to remove add-ons installed by external applications, Facebook Container, which prevents Facebook from tracking across the web, and support for mDNS ICE. Initially, this release was also the first with TLS 1.0 and 1.1 disabled. However, out of concern for access to information during the COVID-19 pandemic, this change was rolled back.

Firefox 75 was released on April 7, 2020. Additions included: a number of improvements with Firefox's revamped address bar, the local cache of all trusted Web PKI Certificate Authority certificates known to Mozilla, the availability of Firefox in Flatpak on Linux, and the integration of Direct Composition on Windows.

Firefox 76 was released on May 5, 2020. Additions included: strengthened protections for online account logins and passwords, with innovative approaches to managing accounts during this critical time, allowing multitasking in Picture-in-Picture, support for Audio Worklets that will allow more complex audio processing like VR and gaming on the web, and two updates to the address bar improving its usability and visibility.

Firefox 77 was released on June 2, 2020. Additions included: pocket recommendations on Firefox' new tab for UK users, a new about:certificate page, and the removal of the browser.urlbar.oneOffSearches preference.

Firefox 78 through 90
Firefox 78 and Firefox 78 ESR were released on June 30, 2020. Among the many additions were: the Protections Dashboard, the addition of the Refresh button to the Uninstaller, a new WebRender rolled out to Windows users with Intel GPUs, the addition of Pocket Recommendations to users in the UK, the requirement of GNU libc 2.17, libstdc++ 4.8.1 and GTK+ 3.14 or newer versions on Linux, the disabling of TLS 1.0 and 1.1 and other improvements, and the addition of Kiosk Mode, client certificates, Service Worker and Push APIs, the Block Autoplay feature, picture-in-picture support, and the management of web certificates in about:certificate in 78 ESR.

Firefox 79 was released on July 28, 2020. Among the many additions were: a new WebRender rolled out to Windows users with Intel and AMD GPUs, the addition of Pocket Recommendations to users in Germany, the fixes for several crashes while using a screen reader, and updates to the password policy, the enabling of Enhanced Tracking Protection by default, and the ability to switch to Dark Mode.

Firefox 80 was released on August 25, 2020, for desktop. Among the many additions were: the setting as the default system PDF viewer, the new add-ons blocklist enabled to improve performance and scalability, support for RTX and Transport-cc for improved call quality in poor network conditions and better bandwidth estimation and better compatibility with many websites using WebRTC.

Firefox 81 was released on September 22, 2020. Among the many additions were: the ability to pause or play audio or video right from the keyboard or headset, the introduction of the Alpenglow theme, the ability to save, manage, and auto-fill credit card information for U.S. and Canada users, the support of Acroform, which allows users to fill in, print, and save supported PDF forms, the automatic revelation of the Bookmarks toolbar, the expansion of .xml, .svg, and .webp, and fixes for browser native HTML audio/video controls.

Firefox 82 was released on October 20, 2020. Changes included various changes to improve the video watching experience, improved page load and start up performance, saving a webpage to Pocket from the Firefox toolbar, and the ability to automatically purge cookies from sites not visited in 30 days.

Firefox 83 was released on November 17, 2020. Among the many additions were: significant updates to SpiderMonkey and JavaScript engine and replacement of the part of the JavaScript engine that helps to compile and display websites for the user, the introduction of the HTTPS-Only Mode, the support of pinch zooming for users with Windows touchscreen devices and touchpads on Mac devices, support of keyboard shortcuts for fast forwarding and rewinding videos in Picture-in-Picture, improved user interface, improved functionality and design for a number of Firefox search features, support of Acroform, and newly supported add-ons: FoxyProxy, Bitwarden, AdGuard AdBlocker, Tomato Clock, LeechBlock NG, and Web Archives.

Firefox 84 was released on December 15, 2020. Among the many additions were: native support for macOS devices built with Apple silicon CPUs, the rollout of WebRender to MacOS Big Sur, Windows devices with Intel Gen 6 GPUs, and Intel laptops running Windows 7 and 8, and an accelerated rendering pipeline for Linux/GNOME/X11 users for the first time, the use of more modern techniques for allocating shared memory on Linux, improving performance and increasing compatibility with Docker, the option to view open tabs side by side in a grid view, the ability to delete downloaded files within the app, the rollout of WebRender to more users on the Mali-G GPU series.

Firefox 85 was released on January 26, 2021. Among the many additions were: protection from supercookies, a type of tracker that can stay hidden in the browser and track users online, even after they have cleared cookies, the ability to save and access bookmarks more easily, the ability of the password manager to have users remove all their saved logins with one click, as opposed to having to delete each login individually, the removal of Adobe Flash support, and added support for the :focus-visible pseudo class.

Firefox 86 was released on February 23, 2021. Among the many additions were: added support for simultaneously watching multiple videos in Picture-in-Picture, improved Print functionality with a cleaner design and better integration with the computer's printer settings, credit card management and auto-fill for users in Canada, notable performance and stability improvements achieved by moving canvas drawing and WebGL drawing to the GPU process, the removal of DTLS 1.0 support or establishing WebRTC's PeerConnections, and the introduction of Total Cookie Protection to Strict Mode (both).

Firefox 87 was released on March 23, 2021. Among the many additions and removals were: the addition of SmartBlock, which provides stand-in scripts so that websites load properly, the new default HTTP Referrer policy (both), the improved "Highlight All" feature on Find in Page, full support for macOS built-in screen reader, VoiceOver, the disabling of the Backspace key as a navigation shortcut for the back navigation button, and the removal of Synced tabs, Recent highlights, and Pocket list from the Library menu, and the rollout of WebRender to more devices, with the following mobile GPUs now supported: Adreno 505, Adreno 506, Mali-T (Android).

Firefox 88 was released on April 19, 2021. Among the many additions and removals were: PDF forms supporting JavaScript embedded in PDF files, localized margin units, smooth pinch-zooming using a touchpad on Linux, isolation of window.name data to the website that created it, the removal of the "Take a Screenshot" feature from the Page Actions menu in the url bar, the disabling of FTP support and a new toggle button in the Network panel for switching between JSON formatted HTTP response and raw data.

Firefox 89 was released on June 1, 2021. Among the many additions and removals were: core experience redesigned and remodernized to be cleaner, more inviting, and easier to use, simplified browser chrome and toolbar, clear, streamlined menus, updated prompts, inspired tab design, reduced number of alerts and messages, lighter iconography, a refined color palette, and more consistent styling throughout, enhancement of privacy of Private Browsing Mode with Total Cookie Protection, the introduction of the elastic overscroll effect known from many other applications for macOS users, added support for smart zoom, native context menus on macOS, Synced Tabs in the Tabs tray, support for the Event Timing API, and support for the CSS forced-colors media query (both).

Firefox 90 was released on July 13, 2021. Among the many additions and removals were: the application of updates in the background when Firefox is not running on Windows, a new page called about:third-party to help identify compatibility issues caused by third-party applications in Windows, the management of exceptions to HTTPS-Only mode in about:preferences#privacy, working hyperlinks in "Print to PDF", Version 2 of Firefox's SmartBlock feature, the addition of software WebRender for most users without its hardware accelerated version, improved software WebRender performance, removal of FTP support, support for Private Fields in DevTools, support for Fetch Metadata Request Headers, the ability to use client authentication certificates stored in hardware tokens or in Operating System storage, the ability to save, manage, and auto-fill credit card information for users shopping on Firefox, and Back/Forward Cache (aka BFCache) for webpages that use unload event listeners (Android).

Firefox 91 through 101
Firefox 91 and Firefox 91 ESR were released on August 10, 2021. Among the many additions and removals were: a build on Total Cookie Protection, support for logging into Microsoft, work, and school accounts using Windows single sign-on, the return of the Simplify page when printing feature, the addition of a new Scots locale, the address bar providing Switch to Tab results in Private Browsing windows, the automatic enable of High Contrast Mode when "Increase Contrast" is checked on MacOS, catch-up paints for almost all user interactions, the support of Javascript embedded in PDF files, the addition of SmartBlock, protection from supercookies, support of AcroForm, the removal of support for Adobe Flash (ESR), a "Set Firefox as your default browser" message on notification pane for new installs, the addition of eBay Search to help users with their shopping needs, and default autoplay setting updated to Blocking Audio Only (Android).

Firefox 92 was released on September 7, 2021. Among the many additions and removals were: an automatic upgrade to HTTPS using HTTPS RR as Alt-Svc headers, support of full-range color levels for video playback on many systems, support for images containing ICC v4 profiles on macOS, access of macOS share options from the Firefox File menu, the redesign of certificate error pages for better user experience, and added support for Web Authentication API, which allows USB tokens (such as the use of USB or Bluetooth Security Key) for website authentication (Android).

Firefox 93 was released on October 5, 2021. Among the many additions and removals were: support for the new AVIF image format, which is based on the modern and royalty free AV1 video codec, support for filling more forms for PDF viewer, automatic unload of tabs based on their last access time, memory usage, and other attributes for Windows when available system memory is critically low, blocking downloads that rely on insecure connections, protecting against potentially malicious or unsafe downloads, improved web compatibility for privacy protections with SmartBlock 3.0, a new referrer tracking protection in Strict Tracking Protection and Private Browsing, disabling of TLS ciphersuites that use 3DES, the addition of forward, back, and reload buttons in the toolbar on tablets, the auto-fill of logins and passwords by default, and the merging of site security and privacy info into one icon (Android).

Firefox 94 was released on November 2, 2021. Among the many additions and removals were: a selection of six fun seasonal Colorways (available for a limited time only), the usage of Apple's low power mode for fullscreen video on sites such as YouTube and Twitch, the addition of about:unloads, fewer interruptions on Windows because of a background agent that will download and install updates even if Firefox is closed, improved WebGL performance and reduced power consumption for Linux users, the introduction of Site Isolation to better protect all users against side-channel attacks, support for the new Snap Layouts menus when running on Windows 11, reduced CPU usage during socket polling for HTTPS connections, faster storage initialization, improved cold startup by reducing main thread I/O, and the new Inactive Tabs feature (Android).

Firefox 95 was released on December 7, 2021. Among the many additions and removals were: RLBox, a new technology that hardens Firefox against potential security vulnerabilities in third-party libraries, the addition of Firefox download from the Microsoft Store on Windows 10 and 11, reduced CPU usage on macOS in Firefox and WindowServer during event processing, reduced power usage of software decoded video on macOS, especially in fullscreen, the ability to move the Picture-in-Picture toggle button to the opposite side of the video, the enabling of Site Isolation, a User Agent override for Slack.com, which allows Firefox users to use more Call features and have access to Huddles, the new "Homepage" section in the Settings Menu, Hero Images in the "Jump Back In" section, confirmation of snack bar "Auto-close enabled" when a user enables auto-close from the tab tray, and support of Pocket (Thought Provoking Stories section) in Canada.

Firefox 96 was released on January 11, 2022. Among the many additions and removals were: significant improvements in noise-suppression and auto-gain-control as well as slight improvements in echo-cancellation, reduced main-thread load, the default of all cookies to having a SameSite=lax attribute which helps defend against Cross-Site Request Forgery (CSRF) attacks, the selection of printing odd/even pages, history highlights to recently visited sites, the display of better images for recent bookmarks on the home page, and improved "fill link from clipboard for Android 12 (Android).

Firefox 97 was released on February 8, 2022. Among the many additions and removals were: support and display for the new style of scrollbars on Windows 11, improvements to system font loading which makes opening and switching to new tabs faster in certain situations for macOS, removal of the 18 colorway themes of Firefox 94, removal of support for directly generating PostScript for printing on Linux, with the exception of printing to Postscript printers, and the addition of a new prompt when users attempt to leave private browsing with active downloads (Android).

Firefox 98 was released on March 8, 2022. Among the many additions were: a new optimized download flow, in which, instead of prompting every time, files will download automatically, allowing users to choose from a number of built-in search engines to set as their default, the ability to change Wallpapers on Homepage, and the ability to clear cookies and website data for a single domain (Android).

Firefox 99 was released on April 5, 2022. Among the many additions were: the ability to toggle Narrate in ReaderMode with the keyboard shortcut "n", added support for search—with or without diacritics—in the PDF viewer, support for credit card autofill and capture in Germany and France, the ability to clear cookies and data for a single domain, and improved performance of Pocket articles on the homescreen (Android).

Firefox 100 was released on May 3, 2022. Among the many additions were: support for captions/subtitles display on YouTube, Amazon Prime Video, and Netflix videos watched in Picture-in-Picture, which now supports video captions on websites that use WebVTT (Web Video Text Track) format, support for HDR video on macOS, hardware accelerated AV1 video decoding on Windows with supported GPUs, video overlay on Windows for Intel GPUs, reducing power usage during video playback, improved fairness between painting and handling other events, support for credit card autofill and capture in the UK, support for profiling multiple java threads, updated History, and bookmark search (Android).

Firefox 101 was released on May 31, 2022. Among the many additions were: the prefers-contrast media query, which allows sites to detect if the user has requested that web content is presented with a higher (or lower) contrast, all non-configured MIME types that can now be assigned a custom action upon download completion, the use of as many microphones at the same time, during video conferencing, added support for large, small, dynamic viewport units and logical ones (*vi and *vb), added web conferencing support for enumerating and selecting multiple audio input devices through navigator.mediaDevices.enumerateDevices, and added support for using the magnifier on Android 9+ for positioning the cursor in forms on web pages (Android).

Firefox 102 through 114
Firefox 102 and Firefox 102 ESR, released on June 28, 2022, gained the ability to turn off the automatic opening of the download pane, protections against tracking through URL query parameters when Enhanced Tracking Protection is set to "strict", subtitles in Picture-in-Picture (PiP) for sites including HBO Max and Disney+, and improved security by isolating audio decoding into its own sandboxed process.

Firefox 103, released on July 26, 2022, improved responsiveness on macOS during periods of high CPU load by switching to a modern lock API, required fields highlighted in PDF forms, improved performance on high-refresh rate monitors (120 Hz+), improved Picture-in-Picture subtitles, which are now available at Funimation, Dailymotion, Tubi, Hotstar, and SonyLIV, buttons in the Tabs toolbar reachable with Tab, Shift+Tab, and Arrow keys, Windows' "Make text bigger" accessibility setting now affecting all the UI and content pages, rather than only applying to system font sizes, the browser getting pinned to the Windows taskbar during installation on Windows 10 and 11, and the removal of a configuration option to allow SHA-1 signatures in certificates, which are not supported.

Firefox 104 was released on August 23, 2022. Among the many additions and removals were: the availability of subtitles for Disney+ in Picture-in-Picture, support for both the scroll-snap-stop property as well as re-snapping, and the ability of the Firefox profiler to analyze power usage of a website for Apple M1 and Windows 11 only, while the Firefox UI itself will now be throttled for performance and battery usage when minimized or occluded, in the same way background tabs are.

Firefox 105 was released on September 20, 2022. Among the many additions and removals were: an option to print only the current page from the print preview dialog, support for partitioned service workers in third-party contexts, a swipe to navigate (two fingers on a touchpad swiped left or right to perform history back or forward) on Windows, compliance with the User Timing L3 specification, which adds additional optional arguments to the performance.mark and performance.measure methods to provide custom start times, end times, duration, and attached details, faster searching in large lists for individual items, which replaces array.includes and array.indexOf with an optimized SIMD version, support for the Offscreen Canvas DOM API with full context and font support.

Firefox 106 was released on October 18, 2022. Among the many additions and removals were: the possibility to edit PDFs: including writing text, drawing, and adding signatures, the ability to become the default PDF application on Windows systems on setting Firefox as the default browser, the ability to pin the Windows taskbar on Windows 10 and 11 for simpler access, the redesign of private windows to increase the feeling of privacy, swipe-to-navigate (two fingers on a touchpad swiped left or right to perform history back or forward) for Linux users on Wayland, Text Recognition in images for users of macOS 10.15 and higher, the addition of "Firefox View", the introduction of 18 new Colorways with the launch of "Independent Voices" collection, major upgrade to WebRTC capabilities, and wallpapers for the "Independent Voices" collection.

Firefox 107 was released on November 15, 2022. Among the many additions and removals were: improved performance of the instance when Microsoft's IME and Defender retrieve the URL of a focused document in Windows 11 version 22H2, support of power profiling (visualizing performance data recorded from web browsers) on Linux and Mac with Intel CPUs, in addition to Windows 11 and Apple Silicon, a couple of helpful improvements in DevTools making it easier to debug WebExtensions, with a new argument allowing users to automatically open DevTools just in case, and a Reload button in the DevTools toolbox to see the changes, the availability of Total Cookie Protection, and enabled text selection magnifier for website text.

Firefox 108 was released on December 13, 2022. Among the many additions and removals were: enabling by default of import maps, which allow web pages to control the behavior of JavaScript imports, processes used for background tabs getting the use of efficiency mode on Windows 11 to limit resource use, the ability to open the Process manager via the Shift+Esc keyboard shortcut, improved frame scheduling when under load, support for properly color correcting images tagged with ICCv4 profiles, support for the WebMIDI API and a new experimental mechanism for controlling access to dangerous capabilities, the ability to save web pages as PDF files to conveniently access them later from the Downloads folder, and the ability to organize tabs in the tabs tray by long-pressing on a tab.

Firefox 109 was released on January 17, 2023. Among the many additions and removals were: the enabling of Manifest Version 3 (MV3) extension support by default, the enabling of the Arbitrary Code Guard exploit protection in the media playback utility processes, the native HTML date picker for date and datetime inputs being used with a keyboard alone, a built-in dictionary for the Firefox spellchecker for builds in the Spanish and Argentine Spanish locales, and the removal of Colorways.

Firefox 110 was released on February 14, 2023. Major changes included support for importing bookmarks, history, and password data from the Opera GX and Vivaldi web browsers, support for Canvas2D GPU-acceleration, support for GPU "sandboxing" on Windows, and various security fixes along with various improvements made to WebGL to improve performance. There were also various features added for web developers such as support for CSS size container queries.

Firefox 111 was released on March 14, 2023. Among the many additions and removals were: the enabling of Windows native notifications, the ability for Firefox Relay users to opt-in to create Relay email masks directly from the credential manager, the Silhe Friulian (fur) and Sardinian (sc) locales, support of the use of the rel attribute on form elements, allowing the specification of the relationship between the current document and the form target in a simpler, cross-browser way, the enabling of Origin private file system access, a new storage API that enables web applications to store and retrieve data from and to the filesystem in a sandbox, the ability for users to view PDF documents as they browse, and the addition of Total Cookie Protection to Enhanced Tracking Protection's Strict Mode.

Firefox 112 was released on April 11, 2023. Major changes included the ability to reveal passwords in password fields, the ability to use the middle click button on a mouse to close tabs in the tab list, along with the ability to use the Ctrl + Shift + T keyboard shortcut to restore a previous browser session, among other changes and bug fixes.

Firefox 113 was released on May 9, 2023. Major changes included enhanced Picture-in-Picture; private windows protecting users even better by blocking third-party cookies and storage of content trackers; the inclusion of special characters in passwords generated by the browser; support for AV1 Image Format files containing animations (AVIS), improving support for AVIF images across the web; a tighter Windows GPU sandbox; and the availability of the browser in the Tajik (tg) language.

Firefox 114 was released on June 6, 2023. Major changes included an added UI to manage the DNS over HTTPS exception list; the accessibility of the Bookmarks menu by adding the Bookmarks menu button to the toolbar, the ability for the user to restrict searches to their local browsing history by selecting Search history from the History, Library or Application menu buttons; the ability for macOS users to capture video from their cameras in all supported native resolutions, enabling resolutions higher than 1280x720; the possibility for users to reorder the extensions listed in the extensions panel; the preference of FIDO2 / WebAuthn authenticators over USB; the availability of Pocket Recommended content in France, Italy, and Spain (desktop); and the Open in app button in PDF viewer opening PDFs in an external app (Android).

Firefox 115 through 127
Firefox 115 and Firefox 115 ESR were released on July 4, 2023. Major changes included the ability to bring over payment methods saved in Chrome-based browsers to the browser; the enabling of hardware video decoding for Intel GPUs on Linux; the close buttons on the Tab Manager dropdown; a refreshed and streamlined user interface for importing data in from other browsers; the ability for users without platform support for H264 video decoding to fallback to Cisco's OpenH264 plugin for playback; the ability for middle clicks on the new tab button to open the xclipboard contents in the new tab on Linux (desktop); and the address button's new search bar that allows users to easily switch between search engines and search their bookmarks and browsing history (Android).

Firefox 116 was released on August 1, 2023. Starting with Firefox 116, Microsoft Windows support is exclusively for Windows 10 and above. Major changes included the sidebar switcher allowing users to access Bookmarks, History and Synced Tabs panels easily, quickly switch between them, move the sidebar to another side of the browser window, or close the sidebar; available access to the release notes in the update notification prompt in the form of a "Learn More" link whenever an update is available in English locales; the ability for users to copy any file from their operating system and paste it into the browser; the volume slider in Picture-in-Picture; the possibility to edit existing text annotations; the improvement of the upload performance of HTTP/2 on those with a higher bandwidth delay product; added support for the dirname attribute to pass text directionality information about input and textarea elements to the server; added support for CSP3 external hashes; the Audio Output Devices API that now enables sites to redirect audio from media elements to permitted output devices (speakers) other than the system default for the user-agent; added upport for proper BYOB readers on Fetch and WebTransport, which allows developers to prepare their ArrayBuffer so that it can be reused for read requests and thus saves memory allocation (desktop); and fixes to pull-to-refresh issues and desktop mode's zoom issues on some sites and "Open links in apps" issue when Firefox is not the default browser (Android).

Firefox 117 was released on August 29, 2023. Major changes included the extension of support for credit card autofill to users running the browser in the IT, ES, AT, BE, and PL locales; the ability for macOS users to control the tabability of controls and links via about:preferences; the addition of a dom.event.contextmenu.shift_suppresses_event preference to prevent the context menu from appearing; the browser no longer showing its own screen sharing indicator on Wayland desktop environments; the enhancement of web compatibility inspection with the new CSS compatibility tooltip in the Developer Tools Inspector; added support for improved CSS nesting by default; support for,   (allowing creation of a ReadableStream from an (async) iterable), and the   and   CSS properties and the   value (desktop); and support for pasting images into contenteditable & designMode elements (Android).

Firefox 118 was released on September 26, 2023. Major changes included the introduction of automated translation of web content, courtesy of the EU-funded Project Bergamot; the use of the FDLIBM math library on all systems to improve anonymity with Fingerprint Protection via web audio in the browser; the restriction of visibility of website fonts to system fonts and language pack fonts to mitigate font fingerprinting in Private Browsing windows; the availability of Video Effects and background blur on Google Meet; the ability for U.S. Firefox Suggest users to see browser add-on suggestions right in the address bar based on their keywords; support for CSS math functions round, mod, rem, pow, sqrt, hypot, log, exp, abs, and sign; OpaqueResponseBlocking enabled by default (desktop); the availability of printing page content from the browser or share menu; the opening of pinned user shortcuts in an existing tab if it already has the same URL; and the clearing of site data being moved from "Browsing history and site data" to the "Cookies and site data" menu item (Android).

Firefox 119 was released on October 24, 2023. Major changes included the addition of Firefox view and the PDF editor; recently closed tabs now persisting between sessions that don't have automatic session restore enabled; the ability to import extensions from Google Chrome; support for the partitioning of Blob URLs, which mitigates a potential tracking vector that third-party agents could use to track an individual; the restriction of the visibility of website fonts to system fonts and language pack fonts in Enhanced Tracking Protection strict mode to mitigate font fingerprinting; an update to the Storage Access API to improve security while mitigating website breakages and further enabling the phase out of third-party cookies in the browser; the addition of Encrypted Client Hello (ECH), which extends the encryption used in TLS connections to cover more of the handshake and better protect sensitive fields; media sniffing no longer being applied to files served as type ; the ability for the mouse pointer to disappear while typing if the relevant Windows mouse properties system setting is enabled; the inclusion of the Santali (sat) language; a fix for an issue causing unexpected jumps in scroll position on Facebook; several enhancements to the Inactive CSS styles feature, which assists in identifying CSS properties that have no effect on an element; the automatic switch to a raw data view if the JSON is invalid or broken; added support for ARIA reflection for simple attributes and default Accessibility Semantics for Custom Elements; added support for   in Cross-Origin-Embedder-Policy; added CSS attr function for a fallback parameter; easier grouping of items by using the methods   or   (desktop); added support for the   and   on Android 14; and a fix for a crash encountered by some users in fullscreen video (Android).

Firefox 120 was released on November 21, 2023. Major changes included added support for a new "Copy Link Without Site Tracking" feature in the context menu which ensures that copied links no longer contain tracking information; added support for a setting (in Preferences → Privacy & Security) to enable Global Privacy Control and inform websites that the user doesn't want their data to be shared or sold; the enhancement of the Canvas APIs with Fingerprinting Protection for the browser's private windows and ETP-Strict privacy configuration for the protection of users' online privacy; the enabling of Cookie Banner Blocker and URL Tracking Protection by default in private windows for all users in Germany; the import of TLS trust anchors (e.g., certificates) from the operating system root store; the addition of keyboard shortcuts for editing and deleting a selected credential on ; the ability for Ubuntu Linux to import from Chromium when both are installed as Snap packages; added support for corner snapping on Windows and Linux for Picture-in-Picture; the addition of the User Activation API, which allows servers to send resource Link headers before the final HTTP response and improves performance on servers using this feature; the ability for users to use an added devtools feature to simulate browser tabs to be offline; the Style Editor panel's feature of a new "Pretty Print" button located in the footer of the panel, similar to the pretty print button found in the Debugger panel, used to format stylesheets (e.g., those that are minified); the Rules panel within the inspector panel no longer displaying colors in the new CSS Color 4 formats (e.g., OKLCH) as hexadecimal/named colors, ensuring that it matches the original values used; the ability for   and   units to be parsed and computed correctly as lengths; the enabling of WebAssembly GC by default, which allows new languages, such as Dart or Kotlin, to run on the browser (desktop); dozens of new mobile extensions surfacing during the release cycle; and a fix for a tabs tray bug where selecting tabs could accidentally close them instead (Android).

Firefox 121 was released on December 19, 2023. Major changes included a prompt for Windows users to install the Microsoft AV1 Video Extension to enable hardware decoding support for the AV1 video codec from  if not already installed; support for Voice Control commands on macOS systems; a default to the Wayland compositor when available instead of XWayland for Linux users; the ability to force links to always be underlined, which can be enabled in the Browsing section of the Settings menu; the floating button in the PDF viewer to simplify deleting drawings, text, and images added in PDFs; the Firefox Debugger including a new feature: an option to disable the   keyword on the current page; the unification of the focus indicator across the toolbox, which is now larger with improved contrast, featuring a white box-shadow for enhanced visibility on blue backgrounds; added support for the   selector, which authors to match an element that has, or "anchors", at least one element matching its relative selector; added support for the   and   keywords for the text-indent CSS property, offering more convenient paragraph layout options for styles such as bibliographies, poetry, etc.; added support for the   keyword for the text-wrap CSS property, which can improve the appearance of short multi-line text blocks such as long headings or captions by harmonizing the line lengths; added support for the lazy loading iframes, which are only loaded when visible, so non-critical iframes can load later when needed to speed up initial page loads, reduce initial network usage, etc.; added support for tail call elimination in WebAssembly language to improve support for functional languages (desktop); expanded extension capabilities by popular demand, adding new support for over 400 more extensions; the ability for private windows to protect users even better by blocking third-party cookies and storage of content trackers; Enhanced Tracking Protection custom mode including blocking of social trackers by default; a fix for a crash when copying to the clipboard; a fix for a crash when the fullscreen notification was encountered; a fix for rendering issues and crashes on Google Pixel 8 and Samsung Galaxy S22 devices (Android); and various security fixes (both).

Firefox 122 was released on January 23, 2024. Major changes included new displays of images and descriptions for search suggestions when provided by the search engine; improvement in the quality of translated webpages in the translations feature; added support for creating and using passkeys stored in the iCloud Keychain on macOS; the availability of MDN Web Docs article suggestions from Firefox Suggest in the address bar for users searching for web development-related information; the line breaking rules of Web content matching the Unicode Standard, improving Web Browser compatibility for line breaking; a new .deb package for Linux users on Ubuntu, Debian, and Linux Mint; a fix for keyboard navigation in Inspector Rules view; enabled offset-position property which is useful for most of the offset-path values; added support for ray, basic-shape and coord-box to the offset-path CSS property; added support for rect and xywh basic shapes on clip-path and offset-path CSS properties; added support for animating the SVG viewBox attribute using SMIL ; LargestContentfulPaint API, which provides timing information about the largest image or text paint before users interact with a web page; added support for hr in select, allowing websites to easily use separators inside a   element; added support for the showpicker method on   elements; the fallback URL parser for unknown schemes changed to , improving specification adherence and web compatibility; the ArrayBuffer.prototype.transfer proposal methods, which enables transferring ownership of ArrayBuffer data; added support for the Screen Wake Lock API; recognition of the "webauthn" autocomplete token; the ability for scripts to store   data in Private Browsing mode; the tainting of filters that use currentColor as an input to further protect user privacy; Uneven Level Protection Forward Error Correction (ULPFEC) turned on by default (desktop); added default PDF reader; added support for enabling Global Privacy Control; the OS version being reported as "Android 10" for Android's User-Agent string to reduce user fingerprinting information and the risk of some website compatibility issues (Adnroid); and various security fixes (both).

Firefox 123 was released on February 20, 2024. Major changes included the integration of search into Firefox View, allowing the user to search through all of the tabs on each of the section subpages - Recent Browsing, Open Tabs, Recently Closed Tabs, Tabs from other devices, or History; the Web Compatibility Reporting Tool; the ability to translate text in tooltips (i.e. titles) and text displayed in form controls (i.e. placeholder) when translating web pages; the implementation of the address bar settings in the Firefox Settings' Search section; the support for the Network Monitor for saving a response body to disk through the Save Response As context menu item; the implementation of linearRGB interpolation for SVG gradients, as well as the existing sRGB interpolation; the SVG content falling back to use the default replaced element values of 300px width and 150px height and the feImage no longer failing to render; added support for Early Hints by enabling Preload and Modulepreload support; the application of audio echo cancellation to microphone inputs when the audio output is redirected to another device with ; added support for declarative ShadowDOM, providing developers greater flexibility and improved ergonomics when working with ShadowDOMs directly within HTML (desktop); the report of ARM64 Linux's CPU architecture as "x86_64" and ARM and x86 Android's as "armv81" in the User-Agent string and the   and   Web APIs (Android); improved PGO optimizations for macOS ARM64 and Android; the off-main-thread canvas on macOS, Linux and Android; and various security fixes (both).

Firefox 124 was released on March 19, 2024. Major changes included the caret browsing mode now working in the PDF viewer; open tabs now being sorted by either recent activity (which is set by default) or tab order in Firefox View; the population of the Windows taskbar jump list more efficiently, which should allow for a smoother overall browsing experience; the use of the macOS fullscreen API for all types of fullscreen windows; the expansion of Qwant's availability to all languages in the France region along with Belgium, Italy, the Netherlands, Spain, and Switzerland; various security fixes; added support for AbortSignal.any ; the ability to use HTTP(S) and relative URLs when creating WebSockets (desktop); the enabling of Pull to Refresh by default; and added support for HTML drag and drop API (which accepts plain text or HTML text by drop operation from external applications) when using a mouse (Android).

Firefox 125 was released for Android, while Firefox 125.0.1 was released for desktop, both on April 16, 2024. Major changes included added support for the AV1 codec for Encrypted Media Extensions (EME), enabling higher-quality playback from video streaming providers; added support for text highlighting for the PDF viewer; the display of pinned tabs in the Open tabs section for Firefox View; the prompt for U.S. and Canadian users to save their addresses upon submitting an address form, allowing the browser to autofill stored address information in the future; the ability to more proactively block downloads from URLs that are considered to be potentially untrustworthy; the URL Paste Suggestion feature providing a convenient way for users to quickly visit URLs copied to the clipboard in the browser address bar; the ability for users of tab-specific Container add-ons to search in the Address Bar for tabs that are open in different containers; an option to enable Web Proxy Auto-Discovery (WPAD) while configured to use system proxy settings; the tab key now only reaching the first option rather than cycling through all available options in a group of radio buttons where no option is selected, and the ability for the arrow keys to navigate between options as they do when there is a selected option, making keyboard navigation more efficient and consistent; the option to disable the Pause Debugger Overlay that appears over the page content when the debugger pauses JavaScript execution; a new drop-down menu button at the bottom of the source view in the Debugger panel, specifically designed for Source Map related actions; added support for the  global attribute used for designating an element as a popover element; the enabling of WebAssembly multi-memory by default; added support for Unicode Text Segmentation to JavaScript; added support for   and   events on HTMLCanvasElement and OffscreenCanvas to allow user code to recover from context loss with hardware accelerated 2D canvas; added support for the   web API; added support for the   and   keywords of the   CSS property; the   property working in block layout, allowing block direction alignment without needing a flex or grid container; removal of support for   in favor of the more widely-implemented   method (desktop); recognition of the theme selection (Dark, Light, Follow Device) setting on Custom Tabs; various improvements to the "Logins and Passwords" settings menu; removal of "Open in App" button when the browser is set as the default PDF Viewer; removal of the variant and extension of BCP47 in the Accept-Language header of HTTP requests for better interoperability with other browsers (Android); and various security fixes (both).

Firefox 126 was released on May 14, 2024. Major changes included the Copy Without Site Tracking option that can now remove parameters from nested URLs, and includes expanded support for blocking over 300 tracking parameters from copied links, including those from major shopping websites; support for Content-encoding: zstd (zstandard compression), which is an alternative to broti and gzip compression for web content, and can provide higher compression levels for the same CPU used, or conversely lower server CPU use to get the same compression; the addiion of the Catalan language; enabled AV1 hardware decode acceleration on macOS for M3 Macs; added telemetry to create an aggregate count of searches by category to broadly inform search feature development; the temporary disabling of the URL Paste Suggestion feature while a potential performance issue was being investigated; an option to disable/enable the Developer Tools' split console feature; the implementation of URL.parse ; the enabling of the CSS zoom property by default following a lot of web compatibility and standardization work in the CSSWG; added support for CSS Custom  and   pseudo-classes; added support for Screen Wake Lock API; added support for IDBFactory.databases for enumeration of IndexedDB databases (desktop); a fix for issues with the address toolbar on devices with foldable screens; the renaming of "Add-ons" settings to "Extensions" (Android); and various security fixes (both).

Firefox 127 was released on June 11, 2024. Major changes included setting the browser to auto-launch, which optimizes efficiency in our browser-centric digital routines, eliminating manual startup delays and facilitating immediate web access; the enabling of DNS prefetching for HTTPS documents via the  link hint; the Close duplicate tabs command available from the List all tabs widget in the tab bar or a tab context menu; the ability to autimatically upgrade, , and elements from HTTP to HTTPS if they are embedded within an HTTPS page; the requirement of a device sign-in when accessing and filling stored passwords in the Password Manager about:logins page in macOS and Windows; the report of the CPU architecture for 32-bit x86 Linux as x86_64 in the User-Agent string and   and   Web APIs; links and other focusable elements now tab-navigable by default on macOS, instead of following macOS' "Keyboard navigation" setting; support of the Screenshots feature for taking screenshots of file types like SVG, XML, and more as well as various about: pages within the browser; the screenshot tool being more accessible to everyone by implementing new keyboard shortcuts and adding theme compatibility and High Contrast Mode (HCM) support; improvement of performance for capturing large screenshots; the enabling of   (desktop); a new Passwords item added to the three-dot menu; numpad on a physical keyboard being used to commit URLs entered in the toolbar; Web content translation; improvement of compiler optimization settings, improving responsiveness, reducing page load times, and extending battery life; the Recently Saved section home page changed into the Bookmarks section (Android); and various security fixes (both).

Firefox 128 through 135
Firefox 128 and Firefox 128 ESR were released on July 9, 2024. Major changes included the ability to translate selections of text and hyperlinked text to other languages from the context menu; the ability to show recent searches or currently trending searches when U.S. and Canadian users open the Address Bar to get them back to their previous search session or inspire the next one; a simpler and more unified dialog for clearing user data, which provides insights into the site data size corresponding to the selected time range in addition to streamlining data categories; added support for playback of protected content from streaming sites like Netflix while in Private Browsing mode; added support for the experimental Privacy Preserving Attribution API, which provides an alternative to user tracking for ad attribution; microphone capture through getUserMedia now using system-provided voice processing when applicable, improving audio quality on macOS; the Saraiki (skr) language; the proxy of DNS by default when using SOCKS v5, avoiding leaking DNS queries to the network when using SOCKS v5 proxies; added support for rendering more  file types inline, rather than requiring them to be downloaded to be viewed; the renewal of the root certificate used to verify add-ons and signed content to avoid upcoming expiration; the display of CSS rules specificity in a tooltip when hovering a CSS rule selector in the Inspector Rules view; the ability for the Inspector panel to flag a custom property declaration as invalid when the value does not match the registered custom property definition; improvements to Inactive CSS displaying a warning when   is used on elements outside of multi-column containers and when properties only applying to replaced elements are used on non-replaced elements; added support for Resizeable ArrayBuffers and Growable SharedArrayBuffers in SpiderMonkey; the ability of the setCodecPreferences method to allow applications to disable the negotiation of specific codecs (including RTX/RED/FEC), and an application to cause a remote peer to prefer the codec that appears first in the list for sending; the change of the  Accept header for images and documents to better align with the Fetch standard and other browsers; added support for   and the CSS properties-and-values API; the provision of a new   method on many objects like Request/Response and Blob that provides a convenient way of getting an Uint8Array typed array (desktop); the ability for users of Android 14 and up to create and use Passkeys in third-party Passkey management applications; the "confirm password" field filled in when suggesting a password; selecting "approximate location" now working when prompted or geolocation permission; the brwoser no longer forcing the display into landscape mode when entering full-screen mode with an audio element playing, or forcing the page to open back in the app if "ask before opening" is set when sharing a link from an app (Android); and various security fixes (both).

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.

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.