Firefox

New

• Tapping the search field on the Firefox for Android homepage now shows your recent searches

Fixed

• HDR videos encoded as 8bit color formats now properly display as HDR in most cases, this fixes several cases of dull gray looking videos that should have been more vibrant.
• Improved audio/video synchronization when changing playback rate on HTMLMediaElement.
• Fixed the Vertical Tabs sidebar not reappearing when the cursor moves to the edge of the screen in full screen mode.

Developer

• Developer Information

Web Platform

• Firefox now supports the at-rule() function for @supports. This allows authors to detect for browser support of specific at-rules, such as @supports at-rule(@scope).
• Firefox now supports the chain value for the CSS overscroll-behavior property.

• Toolbar shortcuts: Long-press a shortcut to edit its setting directly.
• Tab groups: Ungroup and share them more easily.
• Shake to summarize: Adjust shake sensitivity for easier access to page summaries.
• Translations: Now supports Marathi and Urdu.
• Autofill prompts: Now automatically close when you move away from a field.
• Private extension tabs: Tabs opened by extensions while in private browsing now load privately, preventing site data from being left behind in regular browsing.

New

• Firefox on macOS can now be set to open automatically when the computer starts up, from the Startup section of Settings.
• Improved memory and CPU usage when Firefox displays large JPEG images scaled down to fit a page.
• Localized Wikipedia and occasional sponsored suggestions in the address bar are now available in France, Germany, and Italy. These suggestions can be turned off in Firefox Suggest settings.
• On Firefox for Android, the media notification now has previous and next buttons, and a timeline for seeking through audio and video.
• On Firefox for Android, sharing now uses Android's own share sheet on Android 14 and later, including options like Send tab to device and Scan QR code. Older Android versions keep the existing in-app share screen.

Fixed

• On Windows devices with ARM64 processors, WebRTC video calls may now use hardware H264 decoding instead of falling back to software.
• Fixed dragging an inline image to a new position in a rich-text editor replacing it with a long line of text instead of moving it.
• Fixed high-sample-rate FLAC audio in MP4 failing to play on sites such as Bilibili.
• Fixed the find bar becoming permanently unavailable in a tab after reversing the panes in Split View.
• Fixed an issue where dragging a folder and its contents together in the Bookmarks sidebar caused items to move out of the folder.
• Fixed an issue on Windows where Firefox could block an auto-hiding taskbar from showing.
• On Firefox for Android, fixed an issue that could cause Firefox to crash when selecting files from some Android file providers.
• Fixed subtitles not appearing in the Picture-in-Picture window when they are turned on in the video player after Picture-in-Picture has opened.
• On Firefox for Android, fixed an issue where the date picker could allow selecting dates before the minimum allowed date when a maximum date was also specified.
• Fixed some sites failing to load when DNS over HTTPS is enabled and the site does not support HTTPS.

Changed

• Firefox's built-in PDF viewer now starts up to 45% faster.

Enterprise

• The FirefoxHome policy now has a Widgets option, letting administrators control whether the new tab page productivity widgets are available.
• The SitePolicies policy now supports DisableServiceWorkers, letting administrators block service worker registration on specific sites.
• The Windows installer now resolves /INI= paths relative to the installer itself, so deployment tools that unpack to a temporary folder no longer need an absolute path.
• Fixed the DontCheckDefaultBrowser and DefaultBrowserSettingEnabled policies being ignored when Firefox started with a new profile.

Developer

• Developer Information

Web Platform

• text-box-trim now uses the font metrics of a ::first-line pseudo-element when one applies, matching other browsers and the specification.

New

• Firefox on macOS can now be set to open automatically when the computer starts up, from the Startup section of Settings.
• Improved memory and CPU usage when Firefox displays large JPEG images scaled down to fit a page.
• Localized Wikipedia and occasional sponsored suggestions in the address bar are now available in France, Germany, and Italy. These suggestions can be turned off in Firefox Suggest settings.
• On Firefox for Android, the media notification now has previous and next buttons, and a timeline for seeking through audio and video.
• On Firefox for Android, sharing now uses Android's own share sheet on Android 14 and later, including options like Send tab to device and Scan QR code. Older Android versions keep the existing in-app share screen.

Fixed

• On Windows devices with ARM64 processors, WebRTC video calls may now use hardware H264 decoding instead of falling back to software.
• Fixed dragging an inline image to a new position in a rich-text editor replacing it with a long line of text instead of moving it.
• On all devices, WebRTC video calls may now use hardware AV1 decoding instead of falling back to software.
• Fixed high-sample-rate FLAC audio in MP4 failing to play on sites such as Bilibili.
• Fixed the find bar becoming permanently unavailable in a tab after reversing the panes in Split View.
• Fixed an issue on Windows where Firefox could block an auto-hiding taskbar from showing.
• On Firefox for Android, fixed an issue that could cause Firefox to crash when selecting files from some Android file providers.
• Fixed subtitles not appearing in the Picture-in-Picture window when they are turned on in the video player after Picture-in-Picture has opened.
• On Firefox for Android, fixed an issue where the date picker could allow selecting dates before the minimum allowed date when a maximum date was also specified.

Changed

• Firefox's built-in PDF viewer now starts up to 45% faster.

Enterprise

• The FirefoxHome policy now has a Widgets option, letting administrators control whether the new tab page productivity widgets are available.
• The SitePolicies policy now supports DisableServiceWorkers, letting administrators block service worker registration on specific sites.
• The Windows installer now resolves /INI= paths relative to the installer itself, so deployment tools that unpack to a temporary folder no longer need an absolute path.
• Fixed the DontCheckDefaultBrowser and DefaultBrowserSettingEnabled policies being ignored when Firefox started with a new profile.

Developer

• Developer Information

Web Platform

• text-box-trim now uses the font metrics of a ::first-line pseudo-element when one applies, matching other browsers and the specification.

• Toolbar shortcuts: Long-press a shortcut to edit its setting directly.
• Tab groups: Ungroup and share them more easily.
• Shake to summarize: Adjust shake sensitivity for easier access to page summaries.
• Translations: Now supports Marathi and Urdu.
• Autofill prompts: Now automatically close when you move away from a field.
• Private extension tabs: Tabs opened by extensions while in private browsing now load privately, preventing site data from being left behind in regular browsing.

Fixed

• Fixed Firefox becoming unresponsive on some pages that use CSS blur and backdrop filters together. (Bug 2068836)
• Fixed the sidebar not reappearing after restarting Firefox when the "Hide tabs and sidebar" option was turned on. (Bug 2065431)
• Fixed some profile icons not being displayed in the account and application menus. (Bug 2064729, Bug 2067734)
• Fixed the current device being listed among connected devices in the account menu. (Bug 2059763)
• Reference link to 155.0 release notes.

Unresolved

• Standard dynamic range (SDR) video in some formats can appear washed out on macOS. The issue is under investigation and a fix will ship in a future release. (Bug 2068961)

New

• Firefox on macOS can now be set to open automatically when the computer starts up, from the Startup section of Settings.
• Improved memory and CPU usage when Firefox displays large JPEG images scaled down to fit a page.
• Localized Wikipedia and occasional sponsored suggestions in the address bar are now available in France, Germany, and Italy. These suggestions can be turned off in Firefox Suggest settings.
• On Firefox for Android, the media notification now has previous and next buttons, and a timeline for seeking through audio and video.
• On Firefox for Android, sharing now uses Android's own share sheet on Android 14 and later, including options like Send tab to device and Scan QR code. Older Android versions keep the existing in-app share screen.

Fixed

• On Windows devices with ARM64 processors, WebRTC video calls may now use hardware H264 decoding instead of falling back to software.
• Fixed dragging an inline image to a new position in a rich-text editor replacing it with a long line of text instead of moving it.
• On all devices, WebRTC video calls may now use hardware AV1 decoding instead of falling back to software.
• Fixed high-sample-rate FLAC audio in MP4 failing to play on sites such as Bilibili.
• Fixed the find bar becoming permanently unavailable in a tab after reversing the panes in Split View.
• Fixed an issue on Windows where Firefox could block an auto-hiding taskbar from showing.
• On Firefox for Android, fixed an issue that could cause Firefox to crash when selecting files from some Android file providers.
• Fixed subtitles not appearing in the Picture-in-Picture window when they are turned on in the video player after Picture-in-Picture has opened.
• On Firefox for Android, fixed an issue where the date picker could allow selecting dates before the minimum allowed date when a maximum date was also specified.

Changed

• Firefox's built-in PDF viewer now starts up to 45% faster.

Enterprise

• The FirefoxHome policy now has a Widgets option, letting administrators control whether the new tab page productivity widgets are available.
• The SitePolicies policy now supports DisableServiceWorkers, letting administrators block service worker registration on specific sites.
• The Windows installer now resolves /INI= paths relative to the installer itself, so deployment tools that unpack to a temporary folder no longer need an absolute path.
• Fixed the DontCheckDefaultBrowser and DefaultBrowserSettingEnabled policies being ignored when Firefox started with a new profile.

Developer

• Developer Information

Web Platform

• text-box-trim now uses the font metrics of a ::first-line pseudo-element when one applies, matching other browsers and the specification.

New

• Firefox on macOS can now be set to open automatically when the computer starts up, from the Startup section of Settings.
• Improved memory and CPU usage when Firefox displays large JPEG images scaled down to fit a page.
• Localized Wikipedia and occasional sponsored suggestions in the address bar are now available in France, Germany, and Italy. These suggestions can be turned off in Firefox Suggest settings.
• On Firefox for Android, the media notification now has previous and next buttons, and a timeline for seeking through audio and video.
• On Firefox for Android, sharing now uses Android's own share sheet on Android 14 and later, including options like Send tab to device and Scan QR code. Older Android versions keep the existing in-app share screen.

Fixed

• On Windows devices with ARM64 processors, WebRTC video calls may now use hardware H264 decoding instead of falling back to software.
• Fixed dragging an inline image to a new position in a rich-text editor replacing it with a long line of text instead of moving it.
• On all devices, WebRTC video calls may now use hardware AV1 decoding instead of falling back to software.
• Fixed high-sample-rate FLAC audio in MP4 failing to play on sites such as Bilibili.
• Fixed the find bar becoming permanently unavailable in a tab after reversing the panes in Split View.
• Fixed an issue on Windows where Firefox could block an auto-hiding taskbar from showing.
• On Firefox for Android, fixed an issue that could cause Firefox to crash when selecting files from some Android file providers.
• Fixed subtitles not appearing in the Picture-in-Picture window when they are turned on in the video player after Picture-in-Picture has opened.
• On Firefox for Android, fixed an issue where the date picker could allow selecting dates before the minimum allowed date when a maximum date was also specified.

Changed

• Firefox's built-in PDF viewer now starts up to 45% faster.

Enterprise

• The FirefoxHome policy now has a Widgets option, letting administrators control whether the new tab page productivity widgets are available.
• The SitePolicies policy now supports DisableServiceWorkers, letting administrators block service worker registration on specific sites.
• The Windows installer now resolves /INI= paths relative to the installer itself, so deployment tools that unpack to a temporary folder no longer need an absolute path.
• Fixed the DontCheckDefaultBrowser and DefaultBrowserSettingEnabled policies being ignored when Firefox started with a new profile.

Developer

• Developer Information

Web Platform

• text-box-trim now uses the font metrics of a ::first-line pseudo-element when one applies, matching other browsers and the specification.

New

• Smart Window is now available for all users in the USA, Canada, and France to try out! Additionally, Firefox 155 includes many new enhancements:
• New personalized resume conversation starters help users quickly return to topics they’ve been working on.
• Assistant now responds much faster with Exa web search source citations to provide accurate, trustworthy web grounding in roughly 1/5 the time.
• Organize Tabs now suggests better groupings of your related tabs and gives each group a clearer, more descriptive name. This feature is part of a progressive roll out. What is a progressive roll out? Certain new Firefox features are released gradually. This means some users will see the feature before everyone does. This approach helps to get early feedback to catch bugs and improve behavior quickly, meaning more Firefox users overall have a better experience.
• Firefox now shows how many trackers it has blocked in the address bar, making built-in privacy protections easier to see while browsing. The count can be hidden in settings without turning off tracker blocking. This feature is part of a progressive roll out. What is a progressive roll out? Certain new Firefox features are released gradually. This means some users will see the feature before everyone does. This approach helps to get early feedback to catch bugs and improve behavior quickly, meaning more Firefox users overall have a better experience.
• Nintendo Switch Pro and compatible aftermarket controllers now work fully in web games on Windows, with the directional pad and analog sticks correctly mapped.
• Containers can now be reordered in Settings, and the new order is used wherever containers are listed.
• The Translations feature now supports the following languages:
• Marathi
• Urdu

Fixed

• Fixed text disappearing in Microsoft 365 Word Online and other web apps on Linux when typing with certain keyboard layouts.
• Fixed an unnecessary paste confirmation appearing when using the keyboard shortcut to paste without formatting in Google Docs.
• Firefox now recovers from the toolbar and tab strip being left unresponsive when the platform fails to end a tab drag session.
• Fixed text inside buttons not being selectable or copyable, which prevented copying direct messages on X and comments on YouTube.
• Fixed live audio streams such as internet radio stopping when playing in the background.
• Fixed the sound indicator disappearing from a tab that was moved to another window, leaving no way to see or mute what was playing.
• Fixed Firefox preventing Linux systems from going to sleep after a long browsing session.
• Fixed full screen content being letterboxed on MacBooks with a camera notch, most visibly when watching video.
• Fixed arrow-key and Page Up/Down scrolling not working on some pages with embedded content from other sites.
• Fixed characters from some less common scripts appearing as empty boxes on web pages on Windows.
• Fixed WebCodecs VideoEncoder hanging on macOS when encoding a VideoFrame in NV12 format.
• Various security fixes.

Changed

• Firefox now limits CSS to 75 levels of nested blocks and functions, preventing crashes that extremely deep nesting can cause under some circumstances. More deeply nested rules and values no longer parse.
• Firefox now uses firefox-portal-detection.com instead of detectportal.firefox.com to detect captive portals and check network connectivity, so network allowlists referencing the old domain need updating.
• Firefox now opens mailto: links only in response to an explicit user action, so pages can no longer launch the default mail client unprompted.
• PDFs smaller than the paper size can now be enlarged to fill the sheet when printing, by setting the scale above 100%.

Enterprise

• You can find information about policy updates and enterprise-specific bug fixes in the Firefox for Enterprise 155 Release Notes.

Developer

• Developer Information
• The Rules View now offers toggles to emulate the prefers-reduced-motion media feature. Emulation options have also moved into a new panel behind the at-rules (@) button.
• The Debugger in Developer Tools now has a keyboard shortcut, Ctrl+Alt+B (Cmd+Alt+B on macOS), to enable or disable all breakpoints at once.
• The JSON Viewer now displays JSON Lines (JSONL/NDJSON) documents, including inline errors for invalid lines.
• Fixed the Storage panel showing cookies from private windows, containers, and other partitions alongside the inspected page's own cookies.
• Uncaught non-Error exceptions now list their property names in the Console instead of showing only Object.

Web Platform

• The CSS attr() function now supports values of any type, so authors can use attribute values in any property rather than only as strings in the content property.
• Firefox now supports the progress() CSS function.
• Firefox now supports the alpha() CSS function. This is a relative color function that can be used to modify just the alpha component of a given color.
• Firefox now supports the Promise.allKeyed and Promise.allSettledKeyed methods from the await dictionary proposal, which take an object of promises and resolve to an object of results with the same keys.
• Firefox now supports the WebAssembly Compact Import Section proposal, which can reduce the size of WebAssembly modules with many imports.
• Firefox now supports the WebAssembly Wide Arithmetic proposal, which adds 128-bit arithmetic instructions for better performance in cryptography and arbitrary-precision math.
• Firefox now supports QUIC version 2 (RFC 9369) for HTTP/3 connections, and uses it when the server selects it through compatible version negotiation (RFC 9368).
• Support for the non-standard ::-webkit-scrollbar pseudo-element, added in Firefox 153, is now limited to a small list of sites rather than applying universally.
• SVG elements now expose the same URL properties as HTML links, including protocol, host, pathname, and search.
• SVGGraphicsElement.getBBox() now honors its options argument, so bounding boxes can include stroke, markers, and clipping.
• The font-width property is now supported as the standard name for font-stretch.
• A dynamic import() that fails due to a network or HTTP error is no longer cached as a failure in the module map, so retrying the same specifier can now succeed.
• WebTransport now supports send groups (createSendGroup()) for controlling how bandwidth is shared between streams, writable datagram streams (createWritable()), and exportKeyingMaterial() for deriving keys bound to the TLS session. It also adds a draining promise and subprotocol negotiation through the constructor's protocols option and the protocol property.
• Firefox now supports RTCError for data channel failures, RTCSctpTransport.maxChannels, two-byte RTP header extension IDs, and more accurate RTCTransportStats, improving WebRTC interoperability.

Unresolved

• For users with vertical tabs enabled, the sidebar may not persist across Firefox restarts. Vertical tabs can be re-enabled after the restart by clicking the sidebar toolbar button. A fix is currently in development. (Bug 2065431)
• Some sites may load slowly or fail to load on networks that block UDP. This can affect e.g. corporate networks where a proxy or firewall blocks QUIC as part of TLS inspection. To work around it, set network.http.happy_eyeballs_enabled to false with the Preferences policy. A fix is planned for the 155.0.1 release shipping no later than 8-September. (Bug 2063452)

Community Contributions

• With the release of Firefox 155, we are pleased to welcome the developers who contributed their first code change to Firefox in this release, 20 of whom were brand new volunteers! Please join us in thanking each of these diligent and enthusiastic individuals, and take a look at their contributions:
• Artem Bilous: 2056733
• Cameron: 2052559, 2052619
• Colden Cullen: 2060708
• Dan: 1735300
• Fede: 1418178, 2040498, 2046774
• Giulio B: 2048884
• K: 1642578
• Kevin Gosse: 2054036
• Michael F: 2052438
• mikey gough: 2053551
• munawiki: 2055309
• Nathan Leuz: 2053550
• Nirmal Advani: 1804108, 2003174, 2003177, 2003181, 2031618, 2033570, 2046156, 2052618, 2053543, 2053566, 2053568, 2053977, 2058556, 2059866, 2060649
• Priyanshu[:0xanshu]: 1977947
• Richard Van Natta[:rnvannatta]: 2052617
• Ruhollah Majdoddin: 1856645, 2060029, 2061166, 2061348
• Shawn Zivontsis: 2025999
• Simon Rosen: 1875517
• Yuxiao Zhu: 1861034
• Zyphrenn: 2033961, 2059969

Fixed

• Various security fixes.

Developer

• Developer Information
• Reference link to ESR 153.0 release notes.

New

• Firefox on macOS can now be set to open automatically when the computer starts up, from the Startup section of Settings.
• Improved memory and CPU usage when Firefox displays large JPEG images scaled down to fit a page.
• Localized Wikipedia and occasional sponsored suggestions in the address bar are now available in France, Germany, and Italy. These suggestions can be turned off in Firefox Suggest settings.
• On Firefox for Android, the media notification now has previous and next buttons, and a timeline for seeking through audio and video.
• On Firefox for Android, sharing now uses Android's own share sheet on Android 14 and later, including options like Send tab to device and Scan QR code. Older Android versions keep the existing in-app share screen.

Fixed

• On Windows devices with ARM64 processors, WebRTC video calls may now use hardware H264 decoding instead of falling back to software.
• Fixed dragging an inline image to a new position in a rich-text editor replacing it with a long line of text instead of moving it.
• On all devices, WebRTC video calls may now use hardware AV1 decoding instead of falling back to software.
• Fixed high-sample-rate FLAC audio in MP4 failing to play on sites such as Bilibili.
• Fixed the find bar becoming permanently unavailable in a tab after reversing the panes in Split View.
• Fixed an issue on Windows where Firefox could block an auto-hiding taskbar from showing.
• On Firefox for Android, fixed an issue that could cause Firefox to crash when selecting files from some Android file providers.
• Fixed subtitles not appearing in the Picture-in-Picture window when they are turned on in the video player after Picture-in-Picture has opened.
• On Firefox for Android, fixed an issue where the date picker could allow selecting dates before the minimum allowed date when a maximum date was also specified.

Changed

• Firefox's built-in PDF viewer now starts up to 45% faster.

Enterprise

• The FirefoxHome policy now has a Widgets option, letting administrators control whether the new tab page productivity widgets are available.
• The SitePolicies policy now supports DisableServiceWorkers, letting administrators block service worker registration on specific sites.
• The Windows installer now resolves /INI= paths relative to the installer itself, so deployment tools that unpack to a temporary folder no longer need an absolute path.
• Fixed the DontCheckDefaultBrowser and DefaultBrowserSettingEnabled policies being ignored when Firefox started with a new profile.

Developer

• Developer Information

Web Platform

• text-box-trim now uses the font metrics of a ::first-line pseudo-element when one applies, matching other browsers and the specification.

• Toolbar shortcuts: Long-press a shortcut to edit its setting directly.
• Tab groups: Ungroup and share them more easily.
• Shake to summarize: Adjust shake sensitivity for easier access to page summaries.
• Translations: Now supports Marathi and Urdu.
• Autofill prompts: Now automatically close when you move away from a field.
• Private extension tabs: Tabs opened by extensions while in private browsing now load privately, preventing site data from being left behind in regular browsing.

New

• Nintendo Switch Pro and compatible aftermarket controllers now work fully in web games on Windows, with the directional pad and analog sticks correctly mapped.
• Containers can now be reordered in Settings, and the new order is used wherever containers are listed.
• Pages can load faster, with Happy Eyeballs v3 trying several ways of connecting to a website at once and using whichever succeeds first.
• Firefox now shows how many trackers it has blocked in the address bar, making built-in privacy protections easier to see as you browse. You can hide the count in settings without turning off tracker blocking.

Fixed

• Fixed Firefox preventing Linux systems from going to sleep after a long browsing session.
• Fixed arrow-key and Page Up/Down scrolling not working on some pages with embedded content from other sites.
• Fixed characters from some less common scripts appearing as empty boxes on Windows.
• Fixed text disappearing in Microsoft 365 Word Online and other web apps on Linux when typing with certain keyboard layouts.
• Fixed an unnecessary paste confirmation appearing when using the keyboard shortcut to paste without formatting in Google Docs.
• Fixed text inside buttons not being selectable or copyable, which prevented copying direct messages on X and comments on YouTube.
• Fixed live audio streams such as internet radio stopping when playing in the background.
• Firefox now recovers from the toolbar and tab strip being left unresponsive when the platform fails to end a tab drag session.
• Fixed full screen content being letterboxed on MacBooks with a camera notch, most visibly when watching video.
• On Firefox for Android, autofill prompts now dismiss when focus moves away instead of remaining open until back navigation.
• On Firefox for Android, tabs opened by extensions during private browsing now load in private browsing. Previously they appeared private while their content loaded in regular browsing, which could leave site data behind.
• Fixed WebCodecs VideoEncoder hanging on macOS when encoding a VideoFrame in NV12 format.

Changed

• Firefox now opens mailto: links only in response to an explicit user action, so pages can no longer launch the default mail client unprompted.
• PDFs smaller than the paper size can now be enlarged to fill the sheet when printing, by setting the scale above 100%.
• Firefox now uses firefox-portal-detection.com instead of detectportal.firefox.com to detect captive portals and check network connectivity, so network allowlists referencing the old domain need updating.
• Firefox now limits CSS to 75 levels of nested blocks and functions, preventing crashes that extremely deep nesting can cause under some circumstances. More deeply nested rules and values no longer parse.
• On Firefox for Android, long-pressing a toolbar shortcut now offers an Edit shortcut option that goes straight to its setting.

Enterprise

• Added the DisableLaunchOnLogin policy to control whether Firefox launches automatically when users log in to Windows. This policy does not apply to Firefox ESR.
• Fixed an issue where locking certain legacy preferences no longer disabled the corresponding controls in Firefox Settings.

Developer

• Developer Information
• The Rules View now offers toggles to emulate the prefers-reduced-motion media feature. Emulation options have also moved into a new panel behind the @ button.
• The JSON Viewer now displays JSON Lines (JSONL/NDJSON) documents, including inline errors for invalid lines.
• Fixed the Storage panel showing cookies from private windows, containers, and other partitions alongside the inspected page's own cookies.
• Uncaught non-Error exceptions now list their property names in the Console instead of showing only Object.
• The Debugger in Developer Tools now has a keyboard shortcut, Ctrl+Alt+B (Cmd+Alt+B on macOS), to enable or disable all breakpoints at once.

Web Platform

• Firefox now supports the progress() CSS function. This is a math function that can be used in calculations to compute the position of a value relative to a start and an end.
• SVG elements now expose the same URL properties as HTML links, including protocol, host, pathname, and search.
• The CSS attr() function now supports values of any type, so authors can use attribute values in any property rather than only as strings in the content property.
• Firefox now supports the alpha() CSS function. This is a relative color function that can be used to modify just the alpha component of a given color.
• SVGGraphicsElement.getBBox() now honors its options argument, so bounding boxes can include stroke, markers, and clipping.
• Firefox now supports the Promise.allKeyed and Promise.allSettledKeyed methods, which take an object of promises and resolve to an object of results with the same keys.
• Firefox now supports QUIC version 2 (RFC 9369) for HTTP/3 connections, and uses it when the server selects it through compatible version negotiation (RFC 9368).
• Firefox now supports the WebAssembly Compact Import Section proposal, which can reduce the size of WebAssembly modules with many imports.
• Firefox now supports the WebAssembly Wide Arithmetic proposal, which adds 128-bit arithmetic instructions for better performance in cryptography and arbitrary-precision math.
• Support for the non-standard ::-webkit-scrollbar pseudo-element, added in Firefox 153, is now limited to a small list of sites rather than applying universally.
• The font-width property is now supported as the standard name for font-stretch.
• A dynamic import() that fails due to a network or HTTP error is no longer cached as a failure in the module map, so retrying the same specifier can now succeed.
• WebTransport adds send groups (createSendGroup()) for controlling how bandwidth is shared between streams, exportKeyingMaterial() for deriving keys bound to the TLS session, writable datagram streams (createWritable()), a draining promise, and subprotocol negotiation via the constructor's protocols option and the protocol property.
• Firefox 155 improves WebRTC interoperability, adding RTCError for data channel failures, RTCSctpTransport.maxChannels, two-byte RTP header extension IDs, and more accurate RTCTransportStats.

-Fixed an issue where inactive tabs were also being closed when all active tabs were selected for closing. -Fixed an error that was appearing after signing in to the built-in VPN.

Fixed

• Fixed slower access to saved passwords and unexpected Primary Password prompts caused by recent changes to password storage. (Bug 2064411, Bug 2065593, Bug 2063993)
• Fixed an issue where addresses were failing to autofill on some sites. (Bug 2065145, Bug 2063599)
• Fixed Firefox adding a new Start Menu shortcut on Windows every time it started. (Bug 2064652)
• Fixed an issue where connections to local network devices were failing without a permission prompt on some sites loaded over HTTP. (Bug 2059274)
• Fixed a crash that could occur when opening intranet sites that are configured to link to files on a local network share. (Bug 2064648)
• Fixed an issue on Windows where tab titles were cut off at the start when the system font was MS UI Gothic. (Bug 2056856)
• Reference link to 154.0 release notes.

New

• Nintendo Switch Pro and compatible aftermarket controllers now work fully in web games on Windows, with the directional pad and analog sticks correctly mapped.
• Containers can now be reordered in Settings, and the new order is used wherever containers are listed.
• Pages can load faster, with Happy Eyeballs v3 trying several ways of connecting to a website at once and using whichever succeeds first.
• Firefox now shows how many trackers it has blocked in the address bar, making built-in privacy protections easier to see as you browse. You can hide the count in settings without turning off tracker blocking.

Fixed

• Fixed Firefox preventing Linux systems from going to sleep after a long browsing session.
• Fixed arrow-key and Page Up/Down scrolling not working on some pages with embedded content from other sites.
• Fixed characters from some less common scripts appearing as empty boxes on Windows.
• Fixed text disappearing in Microsoft 365 Word Online and other web apps on Linux when typing with certain keyboard layouts.
• Fixed an unnecessary paste confirmation appearing when using the keyboard shortcut to paste without formatting in Google Docs.
• Fixed text inside buttons not being selectable or copyable, which prevented copying direct messages on X and comments on YouTube.
• Fixed live audio streams such as internet radio stopping when playing in the background.
• Firefox now recovers from the toolbar and tab strip being left unresponsive when the platform fails to end a tab drag session.
• Fixed full screen content being letterboxed on MacBooks with a camera notch, most visibly when watching video.
• On Firefox for Android, autofill prompts now dismiss when focus moves away instead of remaining open until back navigation.
• On Firefox for Android, tabs opened by extensions during private browsing now load in private browsing. Previously they appeared private while their content loaded in regular browsing, which could leave site data behind.

Changed

• Firefox now opens mailto: links only in response to an explicit user action, so pages can no longer launch the default mail client unprompted.
• PDFs smaller than the paper size can now be enlarged to fill the sheet when printing, by setting the scale above 100%.
• Firefox now uses firefox-portal-detection.com instead of detectportal.firefox.com to detect captive portals and check network connectivity, so network allowlists referencing the old domain need updating.
• Firefox now limits CSS to 75 levels of nested blocks and functions, preventing crashes that extremely deep nesting can cause under some circumstances. More deeply nested rules and values no longer parse.
• On Firefox for Android, long-pressing a toolbar shortcut now offers an Edit shortcut option that goes straight to its setting.

Enterprise

• Added the DisableLaunchOnLogin policy to control whether Firefox launches automatically when users log in to Windows. This policy does not apply to Firefox ESR.
• Fixed an issue where locking certain legacy preferences no longer disabled the corresponding controls in Firefox Settings.

Developer

• Developer Information
• The Rules View now offers toggles to emulate the prefers-reduced-motion media feature. Emulation options have also moved into a new panel behind the @ button.
• The JSON Viewer now displays JSON Lines (JSONL/NDJSON) documents, including inline errors for invalid lines.
• Fixed the Storage panel showing cookies from private windows, containers, and other partitions alongside the inspected page's own cookies.
• Uncaught non-Error exceptions now list their property names in the Console instead of showing only Object.
• The Debugger in Developer Tools now has a keyboard shortcut, Ctrl+Alt+B (Cmd+Alt+B on macOS), to enable or disable all breakpoints at once.

Web Platform

• Firefox now supports the progress() CSS function. This is a math function that can be used in calculations to compute the position of a value relative to a start and an end.
• SVG elements now expose the same URL properties as HTML links, including protocol, host, pathname, and search.
• The CSS attr() function now supports values of any type, so authors can use attribute values in any property rather than only as strings in the content property.
• Firefox now supports the alpha() CSS function. This is a relative color function that can be used to modify just the alpha component of a given color.
• SVGGraphicsElement.getBBox() now honors its options argument, so bounding boxes can include stroke, markers, and clipping.
• Firefox now supports the Promise.allKeyed and Promise.allSettledKeyed methods, which take an object of promises and resolve to an object of results with the same keys.
• Firefox now supports QUIC version 2 (RFC 9369) for HTTP/3 connections, and uses it when the server selects it through compatible version negotiation (RFC 9368).
• Firefox now supports the WebAssembly Compact Import Section proposal, which can reduce the size of WebAssembly modules with many imports.
• Firefox now supports the WebAssembly Wide Arithmetic proposal, which adds 128-bit arithmetic instructions for better performance in cryptography and arbitrary-precision math.
• Support for the non-standard ::-webkit-scrollbar pseudo-element, added in Firefox 153, is now limited to a small list of sites rather than applying universally.
• The font-width property is now supported as the standard name for font-stretch.
• A dynamic import() that fails due to a network or HTTP error is no longer cached as a failure in the module map, so retrying the same specifier can now succeed.
• WebTransport adds send groups (createSendGroup()) for controlling how bandwidth is shared between streams, exportKeyingMaterial() for deriving keys bound to the TLS session, writable datagram streams (createWritable()), a draining promise, and subprotocol negotiation via the constructor's protocols option and the protocol property.
• Firefox 155 improves WebRTC interoperability, adding RTCError for data channel failures, RTCSctpTransport.maxChannels, two-byte RTP header extension IDs, and more accurate RTCTransportStats.

New

• Nintendo Switch Pro and compatible aftermarket controllers now work fully in web games on Windows, with the directional pad and analog sticks correctly mapped.
• Containers can now be reordered in Settings, and the new order is used wherever containers are listed.
• Pages can load faster, with Happy Eyeballs v3 trying several ways of connecting to a website at once and using whichever succeeds first.
• Firefox now shows how many trackers it has blocked in the address bar, making built-in privacy protections easier to see as you browse. You can hide the count in settings without turning off tracker blocking.

Fixed

• Fixed Firefox preventing Linux systems from going to sleep after a long browsing session.
• Fixed arrow-key and Page Up/Down scrolling not working on some pages with embedded content from other sites.
• Fixed characters from some less common scripts appearing as empty boxes on Windows.
• Fixed text disappearing in Microsoft 365 Word Online and other web apps on Linux when typing with certain keyboard layouts.
• Fixed an unnecessary paste confirmation appearing when using the keyboard shortcut to paste without formatting in Google Docs.
• Fixed text inside buttons not being selectable or copyable, which prevented copying direct messages on X and comments on YouTube.
• Fixed live audio streams such as internet radio stopping when playing in the background.
• Firefox now recovers from the toolbar and tab strip being left unresponsive when the platform fails to end a tab drag session.
• Fixed full screen content being letterboxed on MacBooks with a camera notch, most visibly when watching video.
• On Firefox for Android, autofill prompts now dismiss when focus moves away instead of remaining open until back navigation.
• On Firefox for Android, tabs opened by extensions during private browsing now load in private browsing. Previously they appeared private while their content loaded in regular browsing, which could leave site data behind.

Changed

• Firefox now opens mailto: links only in response to an explicit user action, so pages can no longer launch the default mail client unprompted.
• PDFs smaller than the paper size can now be enlarged to fill the sheet when printing, by setting the scale above 100%.
• Firefox now uses firefox-portal-detection.com instead of detectportal.firefox.com to detect captive portals and check network connectivity, so network allowlists referencing the old domain need updating.
• Firefox now limits CSS to 75 levels of nested blocks and functions, preventing crashes that extremely deep nesting can cause under some circumstances. More deeply nested rules and values no longer parse.
• On Firefox for Android, long-pressing a toolbar shortcut now offers an Edit shortcut option that goes straight to its setting.

Enterprise

• Added the DisableLaunchOnLogin policy to control whether Firefox launches automatically when users log in to Windows. This policy does not apply to Firefox ESR.
• Fixed an issue where locking certain legacy preferences no longer disabled the corresponding controls in Firefox Settings.

Developer

• Developer Information
• The Rules View now offers toggles to emulate the prefers-reduced-motion media feature. Emulation options have also moved into a new panel behind the @ button.
• The JSON Viewer now displays JSON Lines (JSONL/NDJSON) documents, including inline errors for invalid lines.
• Fixed the Storage panel showing cookies from private windows, containers, and other partitions alongside the inspected page's own cookies.
• Uncaught non-Error exceptions now list their property names in the Console instead of showing only Object.
• The Debugger in Developer Tools now has a keyboard shortcut, Ctrl+Alt+B (Cmd+Alt+B on macOS), to enable or disable all breakpoints at once.

Web Platform

• Firefox now supports the progress() CSS function. This is a math function that can be used in calculations to compute the position of a value relative to a start and an end.
• SVG elements now expose the same URL properties as HTML links, including protocol, host, pathname, and search.
• The CSS attr() function now supports values of any type, so authors can use attribute values in any property rather than only as strings in the content property.
• Firefox now supports the alpha() CSS function. This is a relative color function that can be used to modify just the alpha component of a given color.
• SVGGraphicsElement.getBBox() now honors its options argument, so bounding boxes can include stroke, markers, and clipping.
• Firefox now supports the Promise.allKeyed and Promise.allSettledKeyed methods, which take an object of promises and resolve to an object of results with the same keys.
• Firefox now supports QUIC version 2 (RFC 9369) for HTTP/3 connections, and uses it when the server selects it through compatible version negotiation (RFC 9368).
• Firefox now supports the WebAssembly Compact Import Section proposal, which can reduce the size of WebAssembly modules with many imports.
• Firefox now supports the WebAssembly Wide Arithmetic proposal, which adds 128-bit arithmetic instructions for better performance in cryptography and arbitrary-precision math.
• Support for the non-standard ::-webkit-scrollbar pseudo-element, added in Firefox 153, is now limited to a small list of sites rather than applying universally.
• The font-width property is now supported as the standard name for font-stretch.
• A dynamic import() that fails due to a network or HTTP error is no longer cached as a failure in the module map, so retrying the same specifier can now succeed.
• WebTransport adds send groups (createSendGroup()) for controlling how bandwidth is shared between streams, exportKeyingMaterial() for deriving keys bound to the TLS session, writable datagram streams (createWritable()), a draining promise, and subprotocol negotiation via the constructor's protocols option and the protocol property.
• Firefox 155 improves WebRTC interoperability, adding RTCError for data channel failures, RTCSctpTransport.maxChannels, two-byte RTP header extension IDs, and more accurate RTCTransportStats.

New

• Nintendo Switch Pro and compatible aftermarket controllers now work fully in web games on Windows, with the directional pad and analog sticks correctly mapped.
• Containers can now be reordered in Settings, and the new order is used wherever containers are listed.
• Pages can load faster, with Happy Eyeballs v3 trying several ways of connecting to a website at once and using whichever succeeds first.
• Firefox now shows how many trackers it has blocked in the address bar, making built-in privacy protections easier to see as you browse. You can hide the count in settings without turning off tracker blocking.

Fixed

• Fixed Firefox preventing Linux systems from going to sleep after a long browsing session.
• Fixed arrow-key and Page Up/Down scrolling not working on some pages with embedded content from other sites.
• Fixed characters from some less common scripts appearing as empty boxes on Windows.
• Fixed text disappearing in Microsoft 365 Word Online and other web apps on Linux when typing with certain keyboard layouts.
• Fixed an unnecessary paste confirmation appearing when using the keyboard shortcut to paste without formatting in Google Docs.
• Fixed text inside buttons not being selectable or copyable, which prevented copying direct messages on X and comments on YouTube.
• Fixed live audio streams such as internet radio stopping when playing in the background.
• Firefox now recovers from the toolbar and tab strip being left unresponsive when the platform fails to end a tab drag session.
• Fixed full screen content being letterboxed on MacBooks with a camera notch, most visibly when watching video.
• On Firefox for Android, autofill prompts now dismiss when focus moves away instead of remaining open until back navigation.
• On Firefox for Android, tabs opened by extensions during private browsing now load in private browsing. Previously they appeared private while their content loaded in regular browsing, which could leave site data behind.

Changed

• Firefox now opens mailto: links only in response to an explicit user action, so pages can no longer launch the default mail client unprompted.
• PDFs smaller than the paper size can now be enlarged to fill the sheet when printing, by setting the scale above 100%.
• Firefox now uses firefox-portal-detection.com instead of detectportal.firefox.com to detect captive portals and check network connectivity, so network allowlists referencing the old domain need updating.
• Firefox now limits CSS to 75 levels of nested blocks and functions, preventing crashes that extremely deep nesting can cause under some circumstances. More deeply nested rules and values no longer parse.
• On Firefox for Android, long-pressing a toolbar shortcut now offers an Edit shortcut option that goes straight to its setting.

Enterprise

• Added the DisableLaunchOnLogin policy to control whether Firefox launches automatically when users log in to Windows. This policy does not apply to Firefox ESR.
• Fixed an issue where locking certain legacy preferences no longer disabled the corresponding controls in Firefox Settings.

Developer

• Developer Information
• The Rules View now offers toggles to emulate the prefers-reduced-motion media feature. Emulation options have also moved into a new panel behind the @ button.
• The JSON Viewer now displays JSON Lines (JSONL/NDJSON) documents, including inline errors for invalid lines.
• Fixed the Storage panel showing cookies from private windows, containers, and other partitions alongside the inspected page's own cookies.
• Uncaught non-Error exceptions now list their property names in the Console instead of showing only Object.
• The Debugger in Developer Tools now has a keyboard shortcut, Ctrl+Alt+B (Cmd+Alt+B on macOS), to enable or disable all breakpoints at once.

Web Platform

• Firefox now supports the progress() CSS function. This is a math function that can be used in calculations to compute the position of a value relative to a start and an end.
• SVG elements now expose the same URL properties as HTML links, including protocol, host, pathname, and search.
• The CSS attr() function now supports values of any type, so authors can use attribute values in any property rather than only as strings in the content property.
• Firefox now supports the alpha() CSS function. This is a relative color function that can be used to modify just the alpha component of a given color.
• SVGGraphicsElement.getBBox() now honors its options argument, so bounding boxes can include stroke, markers, and clipping.
• Firefox now supports the Promise.allKeyed and Promise.allSettledKeyed methods, which take an object of promises and resolve to an object of results with the same keys.
• Firefox now supports QUIC version 2 (RFC 9369) for HTTP/3 connections, and uses it when the server selects it through compatible version negotiation (RFC 9368).
• Firefox now supports the WebAssembly Compact Import Section proposal, which can reduce the size of WebAssembly modules with many imports.
• Firefox now supports the WebAssembly Wide Arithmetic proposal, which adds 128-bit arithmetic instructions for better performance in cryptography and arbitrary-precision math.
• Support for the non-standard ::-webkit-scrollbar pseudo-element, added in Firefox 153, is now limited to a small list of sites rather than applying universally.
• The font-width property is now supported as the standard name for font-stretch.
• A dynamic import() that fails due to a network or HTTP error is no longer cached as a failure in the module map, so retrying the same specifier can now succeed.
• WebTransport adds send groups (createSendGroup()) for controlling how bandwidth is shared between streams, exportKeyingMaterial() for deriving keys bound to the TLS session, writable datagram streams (createWritable()), a draining promise, and subprotocol negotiation via the constructor's protocols option and the protocol property.
• Firefox 155 improves WebRTC interoperability, adding RTCError for data channel failures, RTCSctpTransport.maxChannels, two-byte RTP header extension IDs, and more accurate RTCTransportStats.

Fixed

• Various security fixes.

Developer

• Developer Information
• Reference link to ESR 153.0 release notes.

New

• Firefox's Local Network Access protections now extend to WebSocket connections. Websites that try to open a WebSocket to a device on the local network will now ask for permission first.
• In Smart Window, Firefox can now suggest groups of related tabs and propose a name for each group. This feature is part of a progressive roll out. What is a progressive roll out? Certain new Firefox features are released gradually. This means some users will see the feature before everyone does. This approach helps to get early feedback to catch bugs and improve behavior quickly, meaning more Firefox users overall have a better experience.
• Firefox on Windows is now a supported browser for NVIDIA GeForce NOW, letting users stream supported PC games directly in the browser.
• Local Firefox profile backups are now available on macOS in addition to Windows and Linux, and backups can be restored across all three platforms.
• Sites can now be exempted from having their cookies and site data cleared on shutdown without also being exempted from tracking protection and other cookie restrictions.
• The full-page Translations feature now translates content.
• The full-page Translations feature now runs language identification on all page loads, resulting in an improved experience for offering translations to users.
• Windows users can now choose a different Firefox app icon in Settings. This is not yet available for MSIX installations, macOS, or Linux, but is coming soon.
• The address bar now includes a Manage AI quick action that opens the AI controls in Settings.
• Performing a hard reload on a page (holding Shift while clicking the Refresh button) now also clears and updates its cached favicons.

Fixed

• Fixed an issue on macOS where closing a browser window could leave behind an invisible window that continued to capture mouse clicks over the area where it used to be.
• Fixed an issue on Windows where an auto-hiding taskbar would not appear until the Firefox window had been minimized and restored after launch.
• Fixed an issue where the Windows taskbar would appear in front of a full screen Picture-in-Picture window.
• Fixed the Vertical Tabs sidebar staying visible in full screen mode. It now hides along with the toolbars and reappears when the cursor moves to the edge of the screen.
• Fixed PDF documents not being scaled correctly in print preview when the Fit to Page Width option is used.
• Various security fixes.

Changed

• Video seeking is now significantly faster on all operating systems, making it quicker to jump to a point in a video.
• Text selected in a PDF is now highlighted the same way as text on a web page, and the highlight color follows operating system settings such as high-contrast mode.
• Firefox View is moving out of the toolbar by default for new profiles and for profiles where it hasn't been used recently. It can still be opened from List all tabs > View all tabs, or added back from the Customize toolbar menu.

Enterprise

• You can find information about policy updates and enterprise-specific bug fixes in the Firefox for Enterprise 154 Release Notes.

Developer

• Developer Information
• The JSON Viewer now shows a breadcrumb path at the bottom for the selected entry.

Web Platform

• Firefox now supports the text-box-trim and text-box-edge CSS properties, and the associated text-box shorthand. These properties control the leading space above and below text, enabling simpler and more consistent vertical spacing and alignment.
• Firefox now supports the sibling-index() and sibling-count() CSS functions. These functions allow an element to be styled with calculations that use its index among its siblings and its total count of siblings (including itself), respectively.
• Added a time picker user interface to and , making selecting a time more accessible and intuitive.
• Added support for the No-Vary-Search HTTP response header for the HTTP disk cache. Servers can now declare which URL query parameters are irrelevant to the response, allowing Firefox to reuse cached resources across parameter variations and improving cache hit rates.
• Firefox now supports new Iterator.prototype.chunks and Iterator.prototype.windows methods that allow consuming an iterator as either overlapping or non-overlapping subsequences of configurable size.
• Firefox now supports Iterator.prototype.includes(), allowing developers to check whether an iterator contains a given value without first converting it to an array.
• Firefox now supports the Iterator.prototype.join method, which allows joining an iterator into a string, similar to Array.prototype.join.

Community Contributions

• With the release of Firefox 154, we are pleased to welcome the developers who contributed their first code change to Firefox in this release, 32 of whom were brand new volunteers! Please join us in thanking each of these diligent and enthusiastic individuals, and take a look at their contributions:
• Ale Camara [:ale]: 2054573
• andra: 2022992, 2046118
• andrea.distefano: 1470011
• Anil Verman: 2040057
• Benoit: 2047559, 2049316, 2050403
• Brieuc Gommard: 2031346, 2049309
• christopher.staite: 2037813
• conor: 1988166
• Cornelius | CE student: 2046119
• Devin Rousso: 2052932
• Diego: 2018728
• elvyria: 2027522
• Gabe: 2049141
• Hagen: 2049264
• Hillwood Yang: 2048250
• Jaimukund Bhan: 2034642
• Kafji: 2051493
• Kometes: 1954212
• Luiz Henrique Vieira: 2050546
• Majed El-Barbari: 2040240
• Marcelo Camargo: 2009295
• Mayank Bansal: 2055744
• muhammad shaikh: 2016932
• Raimund Hook: 2050794
• Rebekah: 2052857
• Riza: 2044167
• Ronak Sheth: 2048099
• taylor: 1419649
• Tim McNulty: 2052560
• Yogeshdangal66: 2031348
• Zehui Xu: 2028402
• 占旭哲: 1992363

Translations: Get more reliable automatic translations when you have multiple languages selected in your system settings. Downloads: Choose the file name and where your downloads are saved. Updated icons: Enjoy a fresh new look with updated icons. Address autofill: Save addresses automatically, with no manual setup required. Bookmark Search: Find bookmarks faster with dedicated search and up to 75 results per search.

New

• Nintendo Switch Pro and compatible aftermarket controllers now work fully in web games on Windows, with the directional pad and analog sticks correctly mapped.
• Containers can now be reordered in Settings, and the new order is used wherever containers are listed.
• Pages can load faster, with Happy Eyeballs v3 trying several ways of connecting to a website at once and using whichever succeeds first.

Fixed

• Fixed Firefox preventing Linux systems from going to sleep after a long browsing session.
• Fixed arrow-key and Page Up/Down scrolling not working on some pages with embedded content from other sites.
• Fixed characters from some less common scripts appearing as empty boxes on Windows.
• Fixed text disappearing in Microsoft 365 Word Online and other web apps on Linux when typing with certain keyboard layouts.
• Fixed an unnecessary paste confirmation appearing when using the keyboard shortcut to paste without formatting in Google Docs.
• Fixed text inside buttons not being selectable or copyable, which prevented copying direct messages on X and comments on YouTube.
• Fixed live audio streams such as internet radio stopping when playing in the background.
• Firefox now recovers from the toolbar and tab strip being left unresponsive when the platform fails to end a tab drag session.
• Fixed full screen content being letterboxed on MacBooks with a camera notch, most visibly when watching video.
• On Firefox for Android, autofill prompts now dismiss when focus moves away instead of remaining open until back navigation.
• On Firefox for Android, tabs opened by extensions during private browsing now load in private browsing. Previously they appeared private while their content loaded in regular browsing, which could leave site data behind.

Changed

• Firefox now opens mailto: links only in response to an explicit user action, so pages can no longer launch the default mail client unprompted.
• PDFs smaller than the paper size can now be enlarged to fill the sheet when printing, by setting the scale above 100%.
• Firefox now uses firefox-portal-detection.com instead of detectportal.firefox.com to detect captive portals and check network connectivity, so network allowlists referencing the old domain need updating.
• Firefox now limits CSS to 75 levels of nested blocks and functions, preventing crashes that extremely deep nesting can cause under some circumstances. More deeply nested rules and values no longer parse.
• On Firefox for Android, long-pressing a toolbar shortcut now offers an Edit shortcut option that goes straight to its setting.

Enterprise

• Added the DisableLaunchOnLogin policy to control whether Firefox launches automatically when users log in to Windows. This policy does not apply to Firefox ESR.
• Fixed an issue where locking certain legacy preferences no longer disabled the corresponding controls in Firefox Settings.

Developer

• Developer Information
• The Rules View now offers toggles to emulate the prefers-reduced-motion media feature. Emulation options have also moved into a new panel behind the @ button.
• The JSON Viewer now displays JSON Lines (JSONL/NDJSON) documents, including inline errors for invalid lines.
• Fixed the Storage panel showing cookies from private windows, containers, and other partitions alongside the inspected page's own cookies.
• Uncaught non-Error exceptions now list their property names in the Console instead of showing only Object.
• The Debugger in Developer Tools now has a keyboard shortcut, Ctrl+Alt+B (Cmd+Alt+B on macOS), to enable or disable all breakpoints at once.

Web Platform

• Firefox now supports the progress() CSS function. This is a math function that can be used in calculations to compute the position of a value relative to a start and an end.
• SVG elements now expose the same URL properties as HTML links, including protocol, host, pathname, and search.
• The CSS attr() function now supports values of any type, so authors can use attribute values in any property rather than only as strings in the content property.
• Firefox now supports the alpha() CSS function. This is a relative color function that can be used to modify just the alpha component of a given color.
• SVGGraphicsElement.getBBox() now honors its options argument, so bounding boxes can include stroke, markers, and clipping.
• Firefox now supports the Promise.allKeyed and Promise.allSettledKeyed methods, which take an object of promises and resolve to an object of results with the same keys.
• Firefox now supports QUIC version 2 (RFC 9369) for HTTP/3 connections, and uses it when the server selects it through compatible version negotiation (RFC 9368).
• Firefox now supports the WebAssembly Compact Import Section proposal, which can reduce the size of WebAssembly modules with many imports.
• Firefox now supports the WebAssembly Wide Arithmetic proposal, which adds 128-bit arithmetic instructions for better performance in cryptography and arbitrary-precision math.
• Support for the non-standard ::-webkit-scrollbar pseudo-element, added in Firefox 153, is now limited to a small list of sites rather than applying universally.
• The font-width property is now supported as the standard name for font-stretch.
• A dynamic import() that fails due to a network or HTTP error is no longer cached as a failure in the module map, so retrying the same specifier can now succeed.
• WebTransport adds send groups (createSendGroup()) for controlling how bandwidth is shared between streams, exportKeyingMaterial() for deriving keys bound to the TLS session, writable datagram streams (createWritable()), a draining promise, and subprotocol negotiation via the constructor's protocols option and the protocol property.
• Firefox 155 improves WebRTC interoperability, adding RTCError for data channel failures, RTCSctpTransport.maxChannels, two-byte RTP header extension IDs, and more accurate RTCTransportStats.

New

• Exceptions for sites that have their cookies & site data cleared on shutdown can now be set without exempting the site from tracking protection and other cookie restrictions.
• Firefox's Local Network Access protections now extends to WebSocket connections. Websites that try to open a WebSocket to a device on your local network will now ask for your permission first.
• In Firefox for Android, improved the reliability of automatic translations for users with multiple languages selected in system settings.
• The address bar now includes a "Manage AI" quick action that opens the AI section of Settings.
• Firefox now gives Windows users the ability to change their default browser icon in Settings (except for MSIX installs). Support for MSIX installs, macOS and Linux is coming soon.
• Performing a hard reload on a page (holding Shift while clicking the Refresh button) now also clears and updates its cached favicons.
• You can now backup your profile locally on macOS devices and restore that profile between windows, macOS and linux. (Learn more)
• When downloading a file in Firefox for Android, you can now customize the file name and the download location. You can also define a custom download location for your downloads.
• In Smart Window, Firefox can now organize your open tabs into groups for you by suggesting groupings of related tabs and naming each one. This feature is part of a progressive roll out. What is a progressive roll out? Certain new Firefox features are released gradually. This means some users will see the feature before everyone does. This approach helps to get early feedback to catch bugs and improve behavior quickly, meaning more Firefox users overall have a better experience.

Fixed

• When using Vertical Tabs in full screen mode, the sidebar is now hidden along with the toolbars, and reappears when moving the cursor to the edge of the screen.
• The display of PDF documents in the print-preview are now scaled correctly when using “Fit to Page Width” option.
• Fixed an issue on macOS where closing a browser window could leave behind an invisible window that continued to capture mouse clicks over the area where it used to be.
• If the Windows taskbar is set to auto-hide, Firefox will no longer require minimizing/maximizing after launch to allow the Windows taskbar to show.

Changed

• Text selected in PDFs is now highlighted clearly like in normal web pages. The selection color also follows OS settings like high-contrast mode.
• Video seeking is now significantly faster on macOS, making scrubbing and jumping to a point in a video much more responsive.
• In Firefox for Android, Bookmarks Search now shows up to 75 results per query, making it easier to find your bookmarks without refining your search.
• Firefox View is moving out of the toolbar by default for new profiles and profiles where it hasn’t been used recently. You can still open it from List all tabs > View all tabs, or add it back from the Customize toolbar menu.

Developer

• Developer Information
• The JSON Viewer now shows a breadcrumb path at the bottom for the selected entry.
• Firefox now supports Iterator.prototype.includes(), allowing developers to check whether an iterator contains a given value without first converting it to an array.
• Firefox now supports the Iterator.prototype.join method that allows joining an iterator into a string, similar to Array.prototype.join.
• Firefox now supports new Iterator.prototype.chunks and Iterator.prototype.windows methods that allow consuming an iterator as either overlapping or non-overlapping subsequences of configurable size.

Web Platform

• Added a time picker user interface to and , making selecting a time more accessible and intuitive.
• Firefox now supports the sibling-index() and sibling-count() CSS functions. These functions allow an element to be styled with calculations that use its index among its siblings and its total count of siblings (including itself), respectively.
• Added support for the No-Vary-Search HTTP response header for the HTTP disk cache. Servers can now declare which URL query parameters are irrelevant to the response, allowing Firefox to reuse cached resources across parameter variations and improving cache hit rates.
• Firefox now supports the text-box-trim and text-box-edge CSS properties, and the associated text-box shorthand. These properties allow you to control the leading space above and below text, enabling simpler and consistent vertical spacing and alignment.

Fixed

• Fixed Firefox becoming unresponsive when clearing browsing history, which could also result in site data being lost. (Bug 2059647)
• Reference link to 153.0.3 release notes.

New

• Exceptions for sites that have their cookies & site data cleared on shutdown can now be set without exempting the site from tracking protection and other cookie restrictions.
• Firefox's Local Network Access protections now extends to WebSocket connections. Websites that try to open a WebSocket to a device on your local network will now ask for your permission first
• In Firefox for Android, improved the reliability of automatic translations for users with multiple languages selected in system settings.
• The address bar now includes a "Manage AI" quick action that opens the AI section of Settings.
• Firefox now gives Windows users the ability to change their default browser icon in Settings (except for MSIX installs). Support for MSIX installs, macOS and Linux is coming soon.
• Performing a hard reload on a page (holding Shift while clicking the Refresh button) now also clears and updates its cached favicons.
• You can now backup your profile locally on macOS devices and restore that profile between windows, macOS and linux. (Learn more)
• When downloading a file in Firefox for Android, you can now customize the file name and the download location. You can also define a custom download location for your downloads.

Fixed

• When using Vertical Tabs in full screen mode, the sidebar is now hidden along with the toolbars, and reappears when moving the cursor to the edge of the screen.

Changed

• Text selected in PDFs is now highlighted clearly like in normal web pages. The selection color also follows OS settings like high-contrast mode.
• Video seeking is now significantly faster on macOS, making scrubbing and jumping to a point in a video much more responsive.
• In Firefox for Android, Bookmarks Search now shows up to 75 results per query, making it easier to find your bookmarks without refining your search.
• Firefox View is moving out of the toolbar by default for new profiles and profiles where it hasn’t been used recently. You can still open it from List all tabs > View all tabs, or add it back from the Customize toolbar menu.

Developer

• Developer Information
• The JSON Viewer now shows a breadcrumb path at the bottom for the selected entry.
• Firefox now supports Iterator.prototype.includes(), allowing developers to check whether an iterator contains a given value without first converting it to an array.

Web Platform

• Added a time picker user interface to and , making selecting a time more accessible and intuitive.
• Firefox now supports the sibling-index() and sibling-count() CSS functions. These functions allow an element to be styled with calculations that use its index among its siblings and its total count of siblings (including itself), respectively.
• Firefox now supports the Iterator.prototype.join method that allows joining an iterator into a string, similar to Array.prototype.join.
• Added support for the No-Vary-Search HTTP response header for the HTTP disk cache. Servers can now declare which URL query parameters are irrelevant to the response, allowing Firefox to reuse cached resources across parameter variations and improving cache hit rates.
• Firefox now supports new Iterator.prototype.chunks and Iterator.prototype.windows methods that allow consuming an iterator as either overlapping or non-overlapping subsequences of configurable size.
• Firefox now supports the text-box-trim and text-box-edge CSS properties, and the associated text-box shorthand. These properties allow you to control the leading space above and below text, enabling simpler and consistent vertical spacing and alignment.

New

• Exceptions for sites that have their cookies & site data cleared on shutdown can now be set without exempting the site from tracking protection and other cookie restrictions.
• Firefox's Local Network Access protections now extends to WebSocket connections. Websites that try to open a WebSocket to a device on your local network will now ask for your permission first
• In Firefox for Android, improved the reliability of automatic translations for users with multiple languages selected in system settings.
• The address bar now includes a "Manage AI" quick action that opens the AI section of Settings.
• Firefox now gives Windows users the ability to change their default browser icon in Settings (except for MSIX installs). Support for MSIX installs, macOS and Linux is coming soon.
• Performing a hard reload on a page (holding Shift while clicking the Refresh button) now also clears and updates its cached favicons.
• You can now backup your profile locally on macOS devices and restore that profile between windows, macOS and linux. (Learn more)
• When downloading a file in Firefox for Android, you can now customize the file name and the download location. You can also define a custom download location for your downloads.

Fixed

• When using Vertical Tabs in full screen mode, the sidebar is now hidden along with the toolbars, and reappears when moving the cursor to the edge of the screen.

Changed

• Text selected in PDFs is now highlighted clearly like in normal web pages. The selection color also follows OS settings like high-contrast mode.
• Video seeking is now significantly faster on macOS, making scrubbing and jumping to a point in a video much more responsive.
• In Firefox for Android, Bookmarks Search now shows up to 75 results per query, making it easier to find your bookmarks without refining your search.
• Firefox View is moving out of the toolbar by default for new profiles and profiles where it hasn’t been used recently. You can still open it from List all tabs > View all tabs, or add it back from the Customize toolbar menu.

Developer

• Developer Information
• The JSON Viewer now shows a breadcrumb path at the bottom for the selected entry.
• Firefox now supports Iterator.prototype.includes(), allowing developers to check whether an iterator contains a given value without first converting it to an array.

Web Platform

• Added a time picker user interface to and , making selecting a time more accessible and intuitive.
• Firefox now supports the sibling-index() and sibling-count() CSS functions. These functions allow an element to be styled with calculations that use its index among its siblings and its total count of siblings (including itself), respectively.
• Firefox now supports the Iterator.prototype.join method that allows joining an iterator into a string, similar to Array.prototype.join.
• Added support for the No-Vary-Search HTTP response header for the HTTP disk cache. Servers can now declare which URL query parameters are irrelevant to the response, allowing Firefox to reuse cached resources across parameter variations and improving cache hit rates.
• Firefox now supports new Iterator.prototype.chunks and Iterator.prototype.windows methods that allow consuming an iterator as either overlapping or non-overlapping subsequences of configurable size.
• Firefox now supports the text-box-trim and text-box-edge CSS properties, and the associated text-box shorthand. These properties allow you to control the leading space above and below text, enabling simpler and consistent vertical spacing and alignment.

New

• Exceptions for sites that have their cookies & site data cleared on shutdown can now be set without exempting the site from tracking protection and other cookie restrictions.
• Firefox's Local Network Access protections now extends to WebSocket connections. Websites that try to open a WebSocket to a device on your local network will now ask for your permission first
• In Firefox for Android, improved the reliability of automatic translations for users with multiple languages selected in system settings.
• The address bar now includes a "Manage AI" quick action that opens the AI section of Settings.
• Firefox now gives Windows users the ability to change their default browser icon in Settings (except for MSIX installs). Support for MSIX installs, macOS and Linux is coming soon.
• Performing a hard reload on a page (holding Shift while clicking the Refresh button) now also clears and updates its cached favicons.
• You can now backup your profile locally on macOS devices and restore that profile between windows, macOS and linux. (Learn more)
• When downloading a file in Firefox for Android, you can now customize the file name and the download location. You can also define a custom download location for your downloads.

Fixed

• When using Vertical Tabs in full screen mode, the sidebar is now hidden along with the toolbars, and reappears when moving the cursor to the edge of the screen.

Changed

• Text selected in PDFs is now highlighted clearly like in normal web pages. The selection color also follows OS settings like high-contrast mode.
• Video seeking is now significantly faster on macOS, making scrubbing and jumping to a point in a video much more responsive.
• In Firefox for Android, Bookmarks Search now shows up to 75 results per query, making it easier to find your bookmarks without refining your search.
• Firefox View is moving out of the toolbar by default for new profiles and profiles where it hasn’t been used recently. You can still open it from List all tabs > View all tabs, or add it back from the Customize toolbar menu.

Developer

• Developer Information
• The JSON Viewer now shows a breadcrumb path at the bottom for the selected entry.
• Firefox now supports Iterator.prototype.includes(), allowing developers to check whether an iterator contains a given value without first converting it to an array.

Web Platform

• Added a time picker user interface to and , making selecting a time more accessible and intuitive.
• Firefox now supports the sibling-index() and sibling-count() CSS functions. These functions allow an element to be styled with calculations that use its index among its siblings and its total count of siblings (including itself), respectively.
• Firefox now supports the Iterator.prototype.join method that allows joining an iterator into a string, similar to Array.prototype.join.
• Added support for the No-Vary-Search HTTP response header for the HTTP disk cache. Servers can now declare which URL query parameters are irrelevant to the response, allowing Firefox to reuse cached resources across parameter variations and improving cache hit rates.
• Firefox now supports new Iterator.prototype.chunks and Iterator.prototype.windows methods that allow consuming an iterator as either overlapping or non-overlapping subsequences of configurable size.
• Firefox now supports the text-box-trim and text-box-edge CSS properties, and the associated text-box shorthand. These properties allow you to control the leading space above and below text, enabling simpler and consistent vertical spacing and alignment.

New

• Smart Window includes several enhancements:
• The suggestion list now shows more results, making it easier to find history and switch to open tabs. (Bug 2019042)
• The assistant can now answer questions directly using web search results from Exa, instead of handing off to a search engine. (Bug 2046183, Bug 2044385) This feature is part of a progressive roll out. What is a progressive roll out? Certain new Firefox features are released gradually. This means some users will see the feature before everyone does. This approach helps to get early feedback to catch bugs and improve behavior quickly, meaning more Firefox users overall have a better experience.

Fixed

• Fixed audio and video failing to play, or hanging when seeking, on websites that load media from a Blob URL. (Bug 2056444)
• Fixed Internet shortcuts dragged from Firefox to the desktop being marked as untrusted on Windows, which caused a security warning every time they were opened. (Bug 2056865)
• Fixed the Bookmarks, History, and other sidebars failing to open when the sidebar is hidden and the password manager has been turned off by an enterprise policy. (Bug 2056857)
• Fixed a Mozilla VPN upgrade offer appearing for people in regions where Mozilla VPN is not sold. (Bug 2058264)
• Fixed frequent Inspector crashes in the Developer Tools on pages where an extension content script had added event listeners. (Bug 2042101)
• Fixed a rare case on Windows where starting Firefox while a partial update was still being applied could leave the installation broken and unable to start. (Bug 2058197, Bug 2058594)
• Reference link to 153.0.1 release notes.

New

• Exceptions for sites that have their cookies & site data cleared on shutdown can now be set without exempting the site from tracking protection and other cookie restrictions.
• Firefox's Local Network Access protections now extends to WebSocket connections. Websites that try to open a WebSocket to a device on your local network will now ask for your permission first
• In Firefox for Android, improved the reliability of automatic translations for users with multiple languages selected in system settings.
• The address bar now includes a "Manage AI" quick action that opens the AI section of Settings.
• Firefox now gives Windows users the ability to change their default browser icon in Settings (except for MSIX installs). Support for MSIX installs, macOS and Linux is coming soon.
• Performing a hard reload on a page (holding Shift while clicking the Refresh button) now also clears and updates its cached favicons.
• You can now backup your profile locally on macOS devices and restore that profile between windows, macOS and linux. (Learn more)
• When downloading a file in Firefox for Android, you can now customize the file name and the download location. You can also define a custom download location for your downloads.

Changed

• Text selected in PDFs is now highlighted clearly like in normal web pages. The selection color also follows OS settings like high-contrast mode.
• Video seeking is now significantly faster on macOS, making scrubbing and jumping to a point in a video much more responsive.
• In Firefox for Android, Bookmarks Search now shows up to 75 results per query, making it easier to find your bookmarks without refining your search.
• Firefox View is moving out of the toolbar by default for new profiles and profiles where it hasn’t been used recently. You can still open it from List all tabs > View all tabs, or add it back from the Customize toolbar menu.

Developer

• Developer Information
• The JSON Viewer now shows a breadcrumb path at the bottom for the selected entry.
• Firefox now supports Iterator.prototype.includes(), allowing developers to check whether an iterator contains a given value without first converting it to an array.

Web Platform

• Added a time picker user interface to and , making selecting a time more accessible and intuitive.
• Firefox now supports the sibling-index() and sibling-count() CSS functions. These functions allow an element to be styled with calculations that use its index among its siblings and its total count of siblings (including itself), respectively.
• Firefox now supports the Iterator.prototype.join method that allows joining an iterator into a string, similar to Array.prototype.join.
• Added support for the No-Vary-Search HTTP response header for the HTTP disk cache. Servers can now declare which URL query parameters are irrelevant to the response, allowing Firefox to reuse cached resources across parameter variations and improving cache hit rates.
• Firefox now supports new Iterator.prototype.chunks and Iterator.prototype.windows methods that allow consuming an iterator as either overlapping or non-overlapping subsequences of configurable size.
• Firefox now supports the text-box-trim and text-box-edge CSS properties, and the associated text-box shorthand. These properties allow you to control the leading space above and below text, enabling simpler and consistent vertical spacing and alignment.

New

• Exceptions for sites that have their cookies & site data cleared on shutdown can now be set without exempting the site from tracking protection and other cookie restrictions.
• Firefox's Local Network Access protections now extends to WebSocket connections. Websites that try to open a WebSocket to a device on your local network will now ask for your permission first
• In Firefox for Android, improved the reliability of automatic translations for users with multiple languages selected in system settings.
• The address bar now includes a "Manage AI" quick action that opens the AI section of Settings.
• Firefox now gives Windows users the ability to change their default browser icon in Settings (except for MSIX installs). Support for MSIX installs, macOS and Linux is coming soon.
• Performing a hard reload on a page (holding Shift while clicking the Refresh button) now also clears and updates its cached favicons.
• You can now backup your profile locally on macOS devices and restore that profile between windows, macOS and linux. (Learn more)
• When downloading a file in Firefox for Android, you can now customize the file name and the download location. You can also define a custom download location for your downloads.

Changed

• Text selected in PDFs is now highlighted clearly like in normal web pages. The selection color also follows OS settings like high-contrast mode.
• Video seeking is now significantly faster on macOS, making scrubbing and jumping to a point in a video much more responsive.
• In Firefox for Android, Bookmarks Search now shows up to 75 results per query, making it easier to find your bookmarks without refining your search.
• Firefox View is moving out of the toolbar by default for new profiles and profiles where it hasn’t been used recently. You can still open it from List all tabs > View all tabs, or add it back from the Customize toolbar menu.

Developer

• Developer Information
• The JSON Viewer now shows a breadcrumb path at the bottom for the selected entry.
• Firefox now supports Iterator.prototype.includes(), allowing developers to check whether an iterator contains a given value without first converting it to an array.

Web Platform

• Added a time picker user interface to and , making selecting a time more accessible and intuitive.
• Firefox now supports the sibling-index() and sibling-count() CSS functions. These functions allow an element to be styled with calculations that use its index among its siblings and its total count of siblings (including itself), respectively.
• Firefox now supports the Iterator.prototype.join method that allows joining an iterator into a string, similar to Array.prototype.join.
• Added support for the No-Vary-Search HTTP response header for the HTTP disk cache. Servers can now declare which URL query parameters are irrelevant to the response, allowing Firefox to reuse cached resources across parameter variations and improving cache hit rates.
• Firefox now supports new Iterator.prototype.chunks and Iterator.prototype.windows methods that allow consuming an iterator as either overlapping or non-overlapping subsequences of configurable size.
• Firefox now supports the text-box-trim and text-box-edge CSS properties, and the associated text-box shorthand. These properties allow you to control the leading space above and below text, enabling simpler and consistent vertical spacing and alignment.

New

• Exceptions for sites that have their cookies & site data cleared on shutdown can now be set without exempting the site from tracking protection and other cookie restrictions.
• Firefox's Local Network Access protections now extends to WebSocket connections. Websites that try to open a WebSocket to a device on your local network will now ask for your permission first
• In Firefox for Android, improved the reliability of automatic translations for users with multiple languages selected in system settings.
• The address bar now includes a "Manage AI" quick action that opens the AI section of Settings.
• Firefox now gives Windows users the ability to change their default browser icon in Settings (except for MSIX installs). Support for MSIX installs, macOS and Linux is coming soon.
• Performing a hard reload on a page (holding Shift while clicking the Refresh button) now also clears and updates its cached favicons.
• You can now backup your profile locally on macOS devices and restore that profile between windows, macOS and linux. (Learn more)
• When downloading a file in Firefox for Android, you can now customize the file name and the download location. You can also define a custom download location for your downloads.

Changed

• Text selected in PDFs is now highlighted clearly like in normal web pages. The selection color also follows OS settings like high-contrast mode.
• Video seeking is now significantly faster on macOS, making scrubbing and jumping to a point in a video much more responsive.
• In Firefox for Android, Bookmarks Search now shows up to 75 results per query, making it easier to find your bookmarks without refining your search.
• Firefox View is moving out of the toolbar by default for new profiles and profiles where it hasn’t been used recently. You can still open it from List all tabs > View all tabs, or add it back from the Customize toolbar menu.

Developer

• Developer Information
• The JSON Viewer now shows a breadcrumb path at the bottom for the selected entry.
• Firefox now supports Iterator.prototype.includes(), allowing developers to check whether an iterator contains a given value without first converting it to an array.

Web Platform

• Added a time picker user interface to and , making selecting a time more accessible and intuitive.
• Firefox now supports the sibling-index() and sibling-count() CSS functions. These functions allow an element to be styled with calculations that use its index among its siblings and its total count of siblings (including itself), respectively.
• Firefox now supports the Iterator.prototype.join method that allows joining an iterator into a string, similar to Array.prototype.join.
• Added support for the No-Vary-Search HTTP response header for the HTTP disk cache. Servers can now declare which URL query parameters are irrelevant to the response, allowing Firefox to reuse cached resources across parameter variations and improving cache hit rates.
• Firefox now supports new Iterator.prototype.chunks and Iterator.prototype.windows methods that allow consuming an iterator as either overlapping or non-overlapping subsequences of configurable size.
• Firefox now supports the text-box-trim and text-box-edge CSS properties, and the associated text-box shorthand. These properties allow you to control the leading space above and below text, enabling simpler and consistent vertical spacing and alignment.

Fixed

• Addressed a startup crash on Windows that could occur after updating Firefox, when some of the application's internal files could not be loaded. Firefox should now start in these cases, although parts of the interface may not display correctly until a further update completes (Bug 2056926).
• Fixed audio playing silently on some music and audio streaming sites after pausing and resuming playback (Bug 2053586).
• Fixed the New Tab page background flashing a few seconds after the page loaded when a custom wallpaper was in use (Bug 2056650).
• Fixed a crash that could occur when a page loaded a frame using a javascript: address (Bug 2054485).
• Fixed a crash that could occur while typing text in an editable area of a page (Bug 2053867).
• Fixed a search engine you had already installed yourself being labeled as "New" when Firefox later started offering the same engine (Bug 2053710).
• Improved pointer lock, used by games and other immersive web content, so that the mouse pointer is less likely to escape the Firefox window (Bug 1255338, Bug 2040628).
• Fixed an issue in the Inspector's Rules view where pseudo-elements could only be expanded once per selected element (Bug 2054525).
• Fixed View Page Source failing to load blob: documents (Bug 2054428).
• Fixed View Page Source timing out on documents that inherit their origin, such as frames using the srcdoc attribute (Bug 2054487).
• Reference link to 153.0 release notes.

Unresolved

• Some Windows users may experience a crash on startup after updating, caused by an incomplete update leaving the Firefox installation in an inconsistent state (Bug 1681745). If you are affected, downloading Firefox from firefox.com and installing it over your existing installation will repair it. Your bookmarks, passwords and other data are stored separately and will not be affected.

New

• Exceptions for sites that have their cookies & site data cleared on shutdown can now be set without exempting the site from tracking protection and other cookie restrictions.
• Firefox's Local Network Access protections now extends to WebSocket connections. Websites that try to open a WebSocket to a device on your local network will now ask for your permission first
• In Firefox for Android, improved the reliability of automatic translations for users with multiple languages selected in system settings.
• The address bar now includes a "Manage AI" quick action that opens the AI section of Settings.
• Firefox now gives Windows users the ability to change their default browser icon in Settings (except for MSIX installs). Support for MSIX installs, macOS and Linux is coming soon.
• Performing a hard reload on a page (holding Shift while clicking the Refresh button) now also clears and updates its cached favicons.
• You can now backup your profile locally on macOS devices and restore that profile between windows, macOS and linux. (Learn more)
• When downloading a file in Firefox for Android, you can now customize the file name and the download location. You can also define a custom download location for your downloads.

Changed

• Text selected in PDFs is now highlighted clearly like in normal web pages. The selection color also follows OS settings like high-contrast mode.
• Video seeking is now significantly faster on macOS, making scrubbing and jumping to a point in a video much more responsive.
• In Firefox for Android, Bookmarks Search now shows up to 75 results per query, making it easier to find your bookmarks without refining your search.
• Firefox View is moving out of the toolbar by default for new profiles and profiles where it hasn’t been used recently. You can still open it from List all tabs > View all tabs, or add it back from the Customize toolbar menu.

Developer

• Developer Information
• The JSON Viewer now shows a breadcrumb path at the bottom for the selected entry.
• Firefox now supports Iterator.prototype.includes(), allowing developers to check whether an iterator contains a given value without first converting it to an array.

Web Platform

• Added a time picker user interface to and , making selecting a time more accessible and intuitive.
• Firefox now supports the sibling-index() and sibling-count() CSS functions. These functions allow an element to be styled with calculations that use its index among its siblings and its total count of siblings (including itself), respectively.
• Firefox now supports the Iterator.prototype.join method that allows joining an iterator into a string, similar to Array.prototype.join.
• Added support for the No-Vary-Search HTTP response header for the HTTP disk cache. Servers can now declare which URL query parameters are irrelevant to the response, allowing Firefox to reuse cached resources across parameter variations and improving cache hit rates.
• Firefox now supports new Iterator.prototype.chunks and Iterator.prototype.windows methods that allow consuming an iterator as either overlapping or non-overlapping subsequences of configurable size.
• Firefox now supports the text-box-trim and text-box-edge CSS properties, and the associated text-box shorthand. These properties allow you to control the leading space above and below text, enabling simpler and consistent vertical spacing and alignment.

New

• Exceptions for sites that have their cookies & site data cleared on shutdown can now be set without exempting the site from tracking protection and other cookie restrictions.
• Firefox's Local Network Access protections now extends to WebSocket connections. Websites that try to open a WebSocket to a device on your local network will now ask for your permission first
• In Firefox for Android, improved the reliability of automatic translations for users with multiple languages selected in system settings.
• The address bar now includes a "Manage AI" quick action that opens the AI section of Settings.
• Firefox now gives Windows users the ability to change their default browser icon in Settings (except for MSIX installs). Support for MSIX installs, macOS and Linux is coming soon.
• Performing a hard reload on a page (holding Shift while clicking the Refresh button) now also clears and updates its cached favicons.
• You can now backup your profile locally on macOS devices and restore that profile between windows, macOS and linux. (Learn more)
• When downloading a file in Firefox for Android, you can now customize the file name and the download location. You can also define a custom download location for your downloads.

Changed

• Text selected in PDFs is now highlighted clearly like in normal web pages. The selection color also follows OS settings like high-contrast mode.
• Video seeking is now significantly faster on macOS, making scrubbing and jumping to a point in a video much more responsive.
• In Firefox for Android, Bookmarks Search now shows up to 75 results per query, making it easier to find your bookmarks without refining your search.
• Firefox View is moving out of the toolbar by default for new profiles and profiles where it hasn’t been used recently. You can still open it from List all tabs > View all tabs, or add it back from the Customize toolbar menu.

Developer

• Developer Information
• The JSON Viewer now shows a breadcrumb path at the bottom for the selected entry.
• Firefox now supports Iterator.prototype.includes(), allowing developers to check whether an iterator contains a given value without first converting it to an array.

Web Platform

• Added a time picker user interface to and , making selecting a time more accessible and intuitive.
• Firefox now supports the sibling-index() and sibling-count() CSS functions. These functions allow an element to be styled with calculations that use its index among its siblings and its total count of siblings (including itself), respectively.
• Firefox now supports the Iterator.prototype.join method that allows joining an iterator into a string, similar to Array.prototype.join.
• Added support for the No-Vary-Search HTTP response header for the HTTP disk cache. Servers can now declare which URL query parameters are irrelevant to the response, allowing Firefox to reuse cached resources across parameter variations and improving cache hit rates.
• Firefox now supports new Iterator.prototype.chunks and Iterator.prototype.windows methods that allow consuming an iterator as either overlapping or non-overlapping subsequences of configurable size.
• Firefox now supports the text-box-trim and text-box-edge CSS properties, and the associated text-box shorthand. These properties allow you to control the leading space above and below text, enabling simpler and consistent vertical spacing and alignment.

New

• Exceptions for sites that have their cookies & site data cleared on shutdown can now be set without exempting the site from tracking protection and other cookie restrictions.
• Firefox's Local Network Access protections now extends to WebSocket connections. Websites that try to open a WebSocket to a device on your local network will now ask for your permission first
• In Firefox for Android, improved the reliability of automatic translations for users with multiple languages selected in system settings.
• The address bar now includes a "Manage AI" quick action that opens the AI section of Settings.
• Firefox now gives Windows users the ability to change their default browser icon in Settings (except for MSIX installs). Support for MSIX installs, macOS and Linux is coming soon.
• Performing a hard reload on a page (holding Shift while clicking the Refresh button) now also clears and updates its cached favicons.
• You can now backup your profile locally on macOS devices and restore that profile between windows, macOS and linux. (Learn more)
• When downloading a file in Firefox for Android, you can now customize the file name and the download location. You can also define a custom download location for your downloads.

Changed

• Text selected in PDFs is now highlighted clearly like in normal web pages. The selection color also follows OS settings like high-contrast mode.
• Video seeking is now significantly faster on macOS, making scrubbing and jumping to a point in a video much more responsive.
• In Firefox for Android, Bookmarks Search now shows up to 75 results per query, making it easier to find your bookmarks without refining your search.
• Firefox View is moving out of the toolbar by default for new profiles and profiles where it hasn’t been used recently. You can still open it from List all tabs > View all tabs, or add it back from the Customize toolbar menu.

Developer

• Developer Information
• The JSON Viewer now shows a breadcrumb path at the bottom for the selected entry.
• Firefox now supports Iterator.prototype.includes(), allowing developers to check whether an iterator contains a given value without first converting it to an array.

Web Platform

• Added a time picker user interface to and , making selecting a time more accessible and intuitive.
• Firefox now supports the sibling-index() and sibling-count() CSS functions. These functions allow an element to be styled with calculations that use its index among its siblings and its total count of siblings (including itself), respectively.
• Firefox now supports the Iterator.prototype.join method that allows joining an iterator into a string, similar to Array.prototype.join.
• Added support for the No-Vary-Search HTTP response header for the HTTP disk cache. Servers can now declare which URL query parameters are irrelevant to the response, allowing Firefox to reuse cached resources across parameter variations and improving cache hit rates.
• Firefox now supports new Iterator.prototype.chunks and Iterator.prototype.windows methods that allow consuming an iterator as either overlapping or non-overlapping subsequences of configurable size.
• Firefox now supports the text-box-trim and text-box-edge CSS properties, and the associated text-box shorthand. These properties allow you to control the leading space above and below text, enabling simpler and consistent vertical spacing and alignment.

New

General

• Firefox now includes a new profile management system that helps you separate your online life into distinct profiles for work, school, vacation planning, or whatever you choose. Profiles can be customized with names, avatars, and color themes while keeping tabs, bookmarks, passwords, and browsing history separate. Built-in profile backup and restore also makes it easier to migrate to a new device or recover your browsing data.
• Split View lets you view two webpages side-by-side in a single browser window, with additional options to quickly open links in Split View, rearrange pages, and search open tabs.
• The Firefox address bar has gained several new capabilities, including built-in unit and time zone conversion, quick actions such as muting all browser audio, and direct search results as you type.
• Firefox now supports copying links directly to highlighted text on a webpage for easier sharing.
• Firefox Settings has been redesigned with improved organization and navigation, making it easier to find and customize browser preferences.

AI

Firefox introduced several new AI-powered features, including on-device tab organization, AI-assisted link previews, integrated AI search, and centralized controls for managing AI features. Whenever possible, these features perform processing locally to help protect user privacy.

Sidebar and Tabs

• Firefox continues to improve tab management with enhancements to vertical tabs, tab groups, and the sidebar.
• Tab groups have gained numerous usability improvements, including better support for collapsed groups, previews of grouped tabs, and additional organization options.
• Passwords can now be accessed directly from the Firefox sidebar without opening a separate tab.
• Firefox now supports copying links from one or multiple background tabs directly from the tab context menu, and multiple tabs can be copied or shared in a single action.
• A Send Tab toolbar button is now available through Customize Toolbar.

Security & Privacy

• Firefox has significantly expanded Fingerprinting Protection, making it harder for websites to uniquely identify users in both Standard and Strict Enhanced Tracking Protection modes.
• Enhanced Tracking Protection includes stronger protections against bounce tracking and additional safeguards that restrict websites from accessing local network resources without user permission.
• Firefox now uses Safe Browsing V5 for phishing and malware protection.
• Firefox Password Manager now uses stronger AES-256 encryption to protect stored logins on disk.
• Private Browsing has been enhanced with new controls, including the ability to instantly end a private browsing session and temporarily relax tracker blocking for individual sites when needed for compatibility.

Translations

• Firefox has expanded on-device translation support with many additional languages and continued improvements to translation quality.
• A dedicated translations page now provides an easy way to perform real-time translations directly within Firefox.

Accessibility

• Firefox continues to improve accessibility with enhanced support for assistive technologies, including Windows UI Automation, improved keyboard navigation, more accessible date and time controls, and better support for mathematical content in PDFs.

Windows

• Firefox now supports installing websites as standalone web apps pinned to the Windows taskbar.
• Firefox web apps are also available for Microsoft Store installations.
• Firefox now better integrates with Windows location permissions when websites request geolocation access.

macOS

• Firefox now uses a dedicated GPU process by default, improving stability by allowing graphics failures to recover without restarting the browser.
• WebGPU is now enabled by default on Apple Silicon Macs.

Linux

• Firefox now supports native fractional scaling on Wayland, improving rendering on high-DPI displays.
• Firefox no longer requires a restart after package manager updates and uses less memory on Linux.
• Firefox now supports the XDG Base Directory Specification and ships with RPM packages for Red Hat, Fedora, openSUSE, and other RPM-based distributions.

Fixed

• Various security fixes.

Enterprise

• Enterprise administrators can now centrally manage Firefox's Generative AI features through enterprise policy.
• Fixed a performance regression affecting native messaging, improving responsiveness for enterprise extensions that communicate with external applications.
• Enterprise policy documentation has moved to https://firefox-admin-docs.mozilla.org/.

Developer

• Developer Information

Web Platform

• Firefox now supports the View Transitions API for creating smooth animated transitions between application views.
• WebGPU support has expanded across supported platforms, including Windows and Apple Silicon Macs.
• Added support for several modern web platform APIs, improving compatibility with modern web applications. Notable additions include the Navigation API, URLPattern, Trusted Types, Sanitizer API, and Prioritized Task Scheduling.

New

• High Dynamic Range (HDR) video playback is now available on Windows - this feature needs HDR mode enabled for the display in Windows Settings - Display. Laptop displays that only offer "HDR video streaming" are not supported at this time. Some videos recorded on phones in certain orientations are currently not shown as HDR.
• Containers let you keep separate parts of your online life (work, shopping, personal, banking) logged into different accounts in the same browser window, but keep your cookies and ad tracking isolated inside each container.
• Share any open page with a QR code. Right-click a tab, select Share > Generate QR Code. Great for posters, invitations, banners, and other printed materials.
• It is now possible to merge multiple PDFs by dragging a PDF into the PDF sidebar.
• It is now possible to add images as new pages within PDFs using the Firefox PDF editor.
• Quickly pick and copy a color from any page by typing "pick color", "color picker", or "eyedropper" in the address bar and selecting the "Pick a color" quick action.
• Added support for Apple's system-wide full-screen keyboard command (Globe-F).
• Firefox now verifies and displays Qualified Website Authentication Certificates (QWACs) in accordance with eIDAS regulations.
• Added improved support for videos with overlays so users can more easily access video actions from context menus.
• Firefox now highlights the location permission icon in red whenever a website has access to your location. The permission icon is also now visible on search results pages where it was previously hidden.
• Smart Window:
• See and choose AI models directly from the Smart Window assistant.
• New Tab now includes a familiar address bar for typing websites and searching the web. This feature is part of a progressive roll out. What is a progressive roll out? Certain new Firefox features are released gradually. This means some users will see the feature before everyone does. This approach helps to get early feedback to catch bugs and improve behavior quickly, meaning more Firefox users overall have a better experience.

Firefox Labs

• Firefox Labs can now be opened quickly by typing "labs" or "experiment" in the address bar and selecting the Open Firefox Labs quick action.
• Firefox now offers experimental support for the new JPEG XL image format, which generally provides better compression than WebP, JPEG, PNG, and GIF and is designed to supersede them. You can enable it from the Firefox Labs panel in Settings.

Fixed

• Various security fixes.

Changed

• Extensions can no longer access local files by default. Users can grant or revoke this access via the new "Access local files on your computer" permission, separate from "Access your data for all websites".
• Local Network Access restrictions are now enabled by default for all users. Firefox requires websites to request permission before connecting to devices on your local network or to apps and services on your device.
• Outdated cookie settings have been removed from the Settings UI. Users still in that mode should switch to default behavior "Isolate cross-site cookies". More information

Enterprise

• You can find information about policy updates and enterprise-specific bug fixes in the Firefox for Enterprise 153 Release Notes.

Developer

• Developer Information
• A new "Local Mode" setting in the options panel allows developers to load local directories via custom origins. This simplifies testing for APIs that do not function over standard file:// URLs, removing the need to run a local web server. Multiple directory mappings are supported.

Web Platform

• Firefox now supports a limited subset of the non-standard ::-webkit-scrollbar pseudo-element to improve web compatibility:
• Rules with non-zero width/height disable overlay scrollbars for the affected container.
• display: none on ::-webkit-scrollbar behaves like scrollbar-width: none, hiding the scrollbar.
• @supports selector(::-webkit-scrollbar) now evaluates to true.
• Full styling capabilities (colors, border-radius, etc.) are intentionally not supported.
• The vertical-align property was converted into a shorthand for baseline-source, alignment-baseline, and baseline-shift in Firefox 149. Now, alignment-baseline supports the new keywords alphabetic, ideographic, central, mathematical, and hanging, extending the variety of baselines to choose for alignment.
• Implemented the new popover=hint spec, which removes a series of inconsistent and unexpected behaviors.
• The circle() and ellipse() functions accept two new keywords closest-corner and farthest-corner for their radial size.
• The newly added Error.stackTraceLimit property allows to set the maximal depth of the captured JavaScript error stack as a performance optimization.
• Developers can now use the text import attribute to import text files using the module system.
• The Picture In Picture API exposes a way for web developers to make use of user agent Picture-In-Picture functionality.
• The Intl.LocaleInfo proposal adds the ability to query Locale information, such as week data (first day in a week, weekend start day, weekend end day), text direction and hour cycle used in the Locale.
• The MediaCapabilities.decodingInfo() and MediaCapabilities.encodingInfo() methods now accept the "webrtc" configuration type. This allows a site to query whether a given audio or video configuration can be decoded or encoded for WebRTC and whether doing so will be smooth and/or powerEfficient.
• HTTP Compression Dictionaries is enabled via rollout in 153, it will be made permanent in a future release. This can greatly reduce network traffic size for sites that use it. This feature is part of a progressive roll out. What is a progressive roll out? Certain new Firefox features are released gradually. This means some users will see the feature before everyone does. This approach helps to get early feedback to catch bugs and improve behavior quickly, meaning more Firefox users overall have a better experience.

Unresolved

• Some Windows users may experience a crash on startup after updating, caused by an incomplete update leaving the Firefox installation in an inconsistent state (Bug 1681745). If you are affected, downloading Firefox from firefox.com and installing it over your existing installation will repair it. Your bookmarks, passwords and other data are stored separately and will not be affected.

Community Contributions

• With the release of Firefox 153, we are pleased to welcome the developers who contributed their first code change to Firefox in this release, 15 of whom were brand new volunteers! Please join us in thanking each of these diligent and enthusiastic individuals, and take a look at their contributions:
• Alan Liu: 2009570
• Dineth De SIlva: 2042443
• Freya Arbjerg [:freyacodes]: 2036767
• Garbee: 2045887
• Jessica Foley: 2041062
• John ARNZEN: 2046279
• Max Emig [:maxe]: 230112
• metamuffin: 2045549
• mtan: 2039500
• ozcoder: 2020186
• Pedram Yektamaram: 2042437, 2042438, 2042440, 2042441, 2042442
• Peter Lafreniere [:n8pjl]: 2041463
• Phone Khant Kyaw Swa: 2008877
• pullmana8: 2031735
• Ryan McCartney: 2039853

New

• High Dynamic Range (HDR) video playback is now available on Windows - this feature needs HDR mode enabled for the display in Windows Settings - Display. Laptop displays that only offer "HDR video streaming" are not supported at this time. Some videos recorded on phones in certain orientations are currently not shown as HDR.
• Containers let you keep separate parts of your online life (work, shopping, personal, banking) logged into different accounts in the same browser window, but keep your cookies and ad tracking isolated inside each container.
• It is now possible to merge multiple PDFs by dragging a PDF into the PDF sidebar.
• It is now possible to add images as new pages within PDFs using the Firefox PDF editor.
• Quickly pick and copy a color from any page by typing "pick color", "color picker", or "eyedropper" in the address bar and selecting the "Pick a color" quick action.
• Added support for Apple's system-wide full-screen keyboard command (Globe-F).
• Share any open page with a QR code. Right-click a tab, select Share > Generate QR Code. Great for posters, invitations, banners, and other printed materials. On macOS, you can also right-click the address bar to access the Share menu.
• Firefox now verifies and displays Qualified Website Authentication Certificates (QWACs) in accordance with eIDAS regulations.
• Added improved support for videos with overlays so users can more easily access video actions from context menus.
• Firefox now highlights the location permission icon in red whenever a website has access to your location. The permission icon is also now visible on search results pages where it was previously hidden.

Firefox Labs

• Firefox Labs can now be opened quickly by typing "labs" or "experiment" in the address bar and selecting the Open Firefox Labs quick action.
• Firefox now offers experimental support for the new JPEG XL image format, which generally provides better compression than WebP, JPEG, PNG, and GIF and is designed to supersede them. You can enable it from the Firefox Labs panel in Settings.

Changed

• Extensions can no longer access local files by default. Users can grant or revoke this access via the new "Access local files on your computer" permission, separate from "Access your data for all websites".
• Local Network Access restrictions are now enabled by default for all users. Firefox requires websites to request permission before connecting to devices on your local network or to apps and services on your device.
• Outdated cookie settings have been removed from the Settings UI. Users still in that mode should switch to default behavior "Isolate cross-site cookies". More information

Developer

• Developer Information
• A new "Local Mode" setting in the options panel allows developers to load local directories via custom origins. This simplifies testing for APIs that do not function over standard file:// URLs, removing the need to run a local web server. Multiple directory mappings are supported.

Web Platform

• Firefox now supports a limited subset of the non-standard ::-webkit-scrollbar pseudo-element to improve web compatibility:
• Rules with non-zero width/height disable overlay scrollbars for the affected container.
• display: none on ::-webkit-scrollbar behaves like scrollbar-width: none, hiding the scrollbar.
• @supports selector(::-webkit-scrollbar) now evaluates to true.
• Full styling capabilities (colors, border-radius, etc.) are intentionally not supported.
• Updated HTML parsing rules for elements, aligning with web standards to support future customizable select dropdown features.
• The vertical-align property was converted into a shorthand for baseline-source, alignment-baseline, and baseline-shift in Firefox 149. Now, alignment-baseline supports the new keywords alphabetic, ideographic, central, mathematical, and hanging, extending the variety of baselines to choose for alignment.
• Implemented the new popover=hint spec, which removes a series of inconsistent and unexpected behaviors.
• The circle() and ellipse() functions accept two new keywords closest-corner and farthest-corner for their radial size.
• The newly added Error.stackTraceLimit property allows to set the maximal depth of the captured JavaScript error stack as a performance optimization.
• Developers can now use the text import attribute to import text files using the module system.
• The Picture In Picture API exposes a way for web developers to make use of user agent Picture-In-Picture functionality.
• The Intl.LocaleInfo proposal adds the ability to query Locale information, such as week data (first day in a week, weekend start day, weekend end day), text direction and hour cycle used in the Locale.
• The MediaCapabilities.decodingInfo() and MediaCapabilities.encodingInfo() methods now accept the "webrtc" configuration type. This allows a site to query whether a given audio or video configuration can be decoded or encoded for WebRTC and whether doing so will be smooth and/or powerEfficient.

New

• Smart Window includes several enhancements:
• Select text on a page and get quick access to summarize, explain, and more using the built-in assistant. (Bug 2034921)
• Added a row of shortcuts to New Tab, making it easier to get back to sites. (Bug 2048338) This feature is part of a progressive roll out. What is a progressive roll out? Certain new Firefox features are released gradually. This means some users will see the feature before everyone does. This approach helps to get early feedback to catch bugs and improve behavior quickly, meaning more Firefox users overall have a better experience.

Fixed

• Fixed an issue that prevented email tracking protection from being disabled in the redesigned Firefox Settings. (Bug 2049331)
• Fixed a hang that could occur after using a file picker dialog on macOS 26. (Bug 2053177)
• Fixed the homepage not loading for some enterprise configurations that set it using a legacy autoconfig format. (Bug 2047962)
• Various security fixes.
• Reference link to 152.0.5 release notes.

New

• High Dynamic Range (HDR) video playback is now available on Windows - this feature needs HDR mode enabled for the display in Windows Settings - Display. Laptop displays that only offer "HDR video streaming" are not supported at this time. Some videos recorded on phones in certain orientations are currently not shown as HDR.
• Containers let you keep separate parts of your online life (work, shopping, personal, banking) logged into different accounts in the same browser window, but keep your cookies and ad tracking isolated inside each container.
• It is now possible to merge multiple PDFs by dragging a PDF into the PDF sidebar.
• It is now possible to add images as new pages within PDFs using the Firefox PDF editor.
• Quickly pick and copy a color from any page by typing "pick color", "color picker", or "eyedropper" in the address bar and selecting the "Pick a color" quick action.
• Added support for Apple's system-wide full-screen keyboard command (Globe-F).
• Share any open page with a QR code. Right-click a tab, select Share > Generate QR Code. Great for posters, invitations, banners, and other printed materials. On macOS, you can also right-click the address bar to access the Share menu.
• Firefox now verifies and displays Qualified Website Authentication Certificates (QWACs) in accordance with eIDAS regulations.
• Added improved support for videos with overlays so users can more easily access video actions from context menus.
• Firefox now highlights the location permission icon in red whenever a website has access to your location. The permission icon is also now visible on search results pages where it was previously hidden.

Firefox Labs

• Firefox Labs can now be opened quickly by typing "labs" or "experiment" in the address bar and selecting the Open Firefox Labs quick action.
• Firefox now offers experimental support for the new JPEG XL image format, which generally provides better compression than WebP, JPEG, PNG, and GIF and is designed to supersede them. You can enable it from the Firefox Labs panel in Settings.

Changed

• Extensions can no longer access local files by default. Users can grant or revoke this access via the new "Access local files on your computer" permission, separate from "Access your data for all websites".
• Local Network Access restrictions are now enabled by default for all users. Firefox requires websites to request permission before connecting to devices on your local network or to apps and services on your device.
• Outdated cookie settings have been removed from the Settings UI. Users still in that mode should switch to default behavior "Isolate cross-site cookies". More information

Developer

• Developer Information
• A new "Local Mode" setting in the options panel allows developers to load local directories via custom origins. This simplifies testing for APIs that do not function over standard file:// URLs, removing the need to run a local web server. Multiple directory mappings are supported.

Web Platform

• Firefox now supports a limited subset of the non-standard ::-webkit-scrollbar pseudo-element to improve web compatibility:
• Rules with non-zero width/height disable overlay scrollbars for the affected container.
• display: none on ::-webkit-scrollbar behaves like scrollbar-width: none, hiding the scrollbar.
• @supports selector(::-webkit-scrollbar) now evaluates to true.
• Full styling capabilities (colors, border-radius, etc.) are intentionally not supported.
• Updated HTML parsing rules for elements, aligning with web standards to support future customizable select dropdown features.
• The vertical-align property was converted into a shorthand for baseline-source, alignment-baseline, and baseline-shift in Firefox 149. Now, alignment-baseline supports the new keywords alphabetic, ideographic, central, mathematical, and hanging, extending the variety of baselines to choose for alignment.
• Implemented the new popover=hint spec, which removes a series of inconsistent and unexpected behaviors.
• The circle() and ellipse() functions accept two new keywords closest-corner and farthest-corner for their radial size.
• The newly added Error.stackTraceLimit property allows to set the maximal depth of the captured JavaScript error stack as a performance optimization.
• Developers can now use the text import attribute to import text files using the module system.
• The Picture In Picture API exposes a way for web developers to make use of user agent Picture-In-Picture functionality.
• The Intl.LocaleInfo proposal adds the ability to query Locale information, such as week data (first day in a week, weekend start day, weekend end day), text direction and hour cycle used in the Locale.
• The MediaCapabilities.decodingInfo() and MediaCapabilities.encodingInfo() methods now accept the "webrtc" configuration type. This allows a site to query whether a given audio or video configuration can be decoded or encoded for WebRTC and whether doing so will be smooth and/or powerEfficient.

New

• High Dynamic Range (HDR) video playback is now available on Windows - this feature needs HDR mode enabled for the display in Windows Settings - Display. Laptop displays that only offer "HDR video streaming" are not supported at this time. Some videos recorded on phones in certain orientations are currently not shown as HDR.
• Containers let you keep separate parts of your online life (work, shopping, personal, banking) logged into different accounts in the same browser window, but keep your cookies and ad tracking isolated inside each container.
• It is now possible to merge multiple PDFs by dragging a PDF into the PDF sidebar.
• It is now possible to add images as new pages within PDFs using the Firefox PDF editor.
• Quickly pick and copy a color from any page by typing "pick color", "color picker", or "eyedropper" in the address bar and selecting the "Pick a color" quick action.
• Added support for Apple's system-wide full-screen keyboard command (Globe-F).
• Share any open page with a QR code. Right-click a tab, select Share > Generate QR Code. Great for posters, invitations, banners, and other printed materials. On macOS, you can also right-click the address bar to access the Share menu.
• Firefox now verifies and displays Qualified Website Authentication Certificates (QWACs) in accordance with eIDAS regulations.
• Added improved support for videos with overlays so users can more easily access video actions from context menus.
• Firefox now highlights the location permission icon in red whenever a website has access to your location. The permission icon is also now visible on search results pages where it was previously hidden.

Firefox Labs

• Firefox Labs can now be opened quickly by typing "labs" or "experiment" in the address bar and selecting the Open Firefox Labs quick action.
• Firefox now offers experimental support for the new JPEG XL image format, which generally provides better compression than WebP, JPEG, PNG, and GIF and is designed to supersede them. You can enable it from the Firefox Labs panel in Settings.

Changed

• Extensions can no longer access local files by default. Users can grant or revoke this access via the new "Access local files on your computer" permission, separate from "Access your data for all websites".
• Local Network Access restrictions are now enabled by default for all users. Firefox requires websites to request permission before connecting to devices on your local network or to apps and services on your device.
• Outdated cookie settings have been removed from the Settings UI. Users still in that mode should switch to default behavior "Isolate cross-site cookies". More information

Developer

• Developer Information
• A new "Local Mode" setting in the options panel allows developers to load local directories via custom origins. This simplifies testing for APIs that do not function over standard file:// URLs, removing the need to run a local web server. Multiple directory mappings are supported.

Web Platform

• Firefox now supports a limited subset of the non-standard ::-webkit-scrollbar pseudo-element to improve web compatibility:
• Rules with non-zero width/height disable overlay scrollbars for the affected container.
• display: none on ::-webkit-scrollbar behaves like scrollbar-width: none, hiding the scrollbar.
• @supports selector(::-webkit-scrollbar) now evaluates to true.
• Full styling capabilities (colors, border-radius, etc.) are intentionally not supported.
• Updated HTML parsing rules for elements, aligning with web standards to support future customizable select dropdown features.
• The vertical-align property was converted into a shorthand for baseline-source, alignment-baseline, and baseline-shift in Firefox 149. Now, alignment-baseline supports the new keywords alphabetic, ideographic, central, mathematical, and hanging, extending the variety of baselines to choose for alignment.
• Implemented the new popover=hint spec, which removes a series of inconsistent and unexpected behaviors.
• The circle() and ellipse() functions accept two new keywords closest-corner and farthest-corner for their radial size.
• The newly added Error.stackTraceLimit property allows to set the maximal depth of the captured JavaScript error stack as a performance optimization.
• Developers can now use the text import attribute to import text files using the module system.
• The Picture In Picture API exposes a way for web developers to make use of user agent Picture-In-Picture functionality.
• The Intl.LocaleInfo proposal adds the ability to query Locale information, such as week data (first day in a week, weekend start day, weekend end day), text direction and hour cycle used in the Locale.
• The MediaCapabilities.decodingInfo() and MediaCapabilities.encodingInfo() methods now accept the "webrtc" configuration type. This allows a site to query whether a given audio or video configuration can be decoded or encoded for WebRTC and whether doing so will be smooth and/or powerEfficient.

New

• High Dynamic Range (HDR) video playback is now available on Windows - this feature needs HDR mode enabled for the display in Windows Settings - Display. Laptop displays that only offer "HDR video streaming" are not supported at this time. Some videos recorded on phones in certain orientations are currently not shown as HDR.
• Containers let you keep separate parts of your online life (work, shopping, personal, banking) logged into different accounts in the same browser window, but keep your cookies and ad tracking isolated inside each container.
• It is now possible to merge multiple PDFs by dragging a PDF into the PDF sidebar.
• It is now possible to add images as new pages within PDFs using the Firefox PDF editor.
• Quickly pick and copy a color from any page by typing "pick color", "color picker", or "eyedropper" in the address bar and selecting the "Pick a color" quick action.
• Added support for Apple's system-wide full-screen keyboard command (Globe-F).
• Share any open page with a QR code. Right-click a tab, select Share > Generate QR Code. Great for posters, invitations, banners, and other printed materials. On macOS, you can also right-click the address bar to access the Share menu.
• Firefox now verifies and displays Qualified Website Authentication Certificates (QWACs) in accordance with eIDAS regulations.
• Added improved support for videos with overlays so users can more easily access video actions from context menus.
• Firefox now highlights the location permission icon in red whenever a website has access to your location. The permission icon is also now visible on search results pages where it was previously hidden.

Firefox Labs

• Firefox Labs can now be opened quickly by typing "labs" or "experiment" in the address bar and selecting the Open Firefox Labs quick action.
• Firefox now offers experimental support for the new JPEG XL image format, which generally provides better compression than WebP, JPEG, PNG, and GIF and is designed to supersede them. You can enable it from the Firefox Labs panel in Settings.

Changed

• Extensions can no longer access local files by default. Users can grant or revoke this access via the new "Access local files on your computer" permission, separate from "Access your data for all websites".
• Local Network Access restrictions are now enabled by default for all users. Firefox requires websites to request permission before connecting to devices on your local network or to apps and services on your device.
• Outdated cookie settings have been removed from the Settings UI. Users still in that mode should switch to default behavior "Isolate cross-site cookies". More information

Developer

• Developer Information
• A new "Local Mode" setting in the options panel allows developers to load local directories via custom origins. This simplifies testing for APIs that do not function over standard file:// URLs, removing the need to run a local web server. Multiple directory mappings are supported.

Web Platform

• Firefox now supports a limited subset of the non-standard ::-webkit-scrollbar pseudo-element to improve web compatibility:
• Rules with non-zero width/height disable overlay scrollbars for the affected container.
• display: none on ::-webkit-scrollbar behaves like scrollbar-width: none, hiding the scrollbar.
• @supports selector(::-webkit-scrollbar) now evaluates to true.
• Full styling capabilities (colors, border-radius, etc.) are intentionally not supported.
• Updated HTML parsing rules for elements, aligning with web standards to support future customizable select dropdown features.
• The vertical-align property was converted into a shorthand for baseline-source, alignment-baseline, and baseline-shift in Firefox 149. Now, alignment-baseline supports the new keywords alphabetic, ideographic, central, mathematical, and hanging, extending the variety of baselines to choose for alignment.
• Implemented the new popover=hint spec, which removes a series of inconsistent and unexpected behaviors.
• The circle() and ellipse() functions accept two new keywords closest-corner and farthest-corner for their radial size.
• The newly added Error.stackTraceLimit property allows to set the maximal depth of the captured JavaScript error stack as a performance optimization.
• Developers can now use the text import attribute to import text files using the module system.
• The Picture In Picture API exposes a way for web developers to make use of user agent Picture-In-Picture functionality.
• The Intl.LocaleInfo proposal adds the ability to query Locale information, such as week data (first day in a week, weekend start day, weekend end day), text direction and hour cycle used in the Locale.
• The MediaCapabilities.decodingInfo() and MediaCapabilities.encodingInfo() methods now accept the "webrtc" configuration type. This allows a site to query whether a given audio or video configuration can be decoded or encoded for WebRTC and whether doing so will be smooth and/or powerEfficient.

Fixed

• Fixed the Manage payment methods list in Settings appearing empty when a saved payment card had no expiration date. (Bug 2048383)
• Reference link to 152.0.4 release notes.

New

• High Dynamic Range (HDR) video playback is now available on Windows - this feature needs HDR mode enabled for the display in Windows Settings - Display. Laptop displays that only offer "HDR video streaming" are not supported at this time. Some videos recorded on phones in certain orientations are currently not shown as HDR.
• Containers let you keep separate parts of your online life (work, shopping, personal, banking) logged into different accounts in the same browser window, but keep your cookies and ad tracking isolated inside each container.
• It is now possible to merge multiple PDFs by dragging a PDF into the PDF sidebar.
• It is now possible to add images as new pages within PDFs using the Firefox PDF editor.
• Quickly pick and copy a color from any page by typing "pick color", "color picker", or "eyedropper" in the address bar and selecting the "Pick a color" quick action.
• Added support for Apple's system-wide full-screen keyboard command (Globe-F).
• Share any open page with a QR code. Right-click a tab, select Share > Generate QR Code. Great for posters, invitations, banners, and other printed materials. On macOS, you can also right-click the address bar to access the Share menu.
• Firefox now verifies and displays Qualified Website Authentication Certificates (QWACs) in accordance with eIDAS regulations.
• Added improved support for videos with overlays so users can more easily access video actions from context menus.
• Firefox now highlights the location permission icon in red whenever a website has access to your location. The permission icon is also now visible on search results pages where it was previously hidden.

Firefox Labs

• Firefox Labs can now be opened quickly by typing "labs" or "experiment" in the address bar and selecting the Open Firefox Labs quick action.
• Firefox now offers experimental support for the new JPEG XL image format, which generally provides better compression than WebP, JPEG, PNG, and GIF and is designed to supersede them. You can enable it from the Firefox Labs panel in Settings.

Changed

• Extensions can no longer access local files by default. Users can grant or revoke this access via the new "Access local files on your computer" permission, separate from "Access your data for all websites".
• Local Network Access restrictions are now enabled by default for all users. Firefox requires websites to request permission before connecting to devices on your local network or to apps and services on your device.
• Outdated cookie settings have been removed from the Settings UI. Users still in that mode should switch to default behavior "Isolate cross-site cookies". More information

Developer

• Developer Information
• A new "Local Mode" setting in the options panel allows developers to load local directories via custom origins. This simplifies testing for APIs that do not function over standard file:// URLs, removing the need to run a local web server. Multiple directory mappings are supported.

Web Platform

• Firefox now supports a limited subset of the non-standard ::-webkit-scrollbar pseudo-element to improve web compatibility:
• Rules with non-zero width/height disable overlay scrollbars for the affected container.
• display: none on ::-webkit-scrollbar behaves like scrollbar-width: none, hiding the scrollbar.
• @supports selector(::-webkit-scrollbar) now evaluates to true.
• Full styling capabilities (colors, border-radius, etc.) are intentionally not supported.
• Updated HTML parsing rules for elements, aligning with web standards to support future customizable select dropdown features.
• The vertical-align property was converted into a shorthand for baseline-source, alignment-baseline, and baseline-shift in Firefox 149. Now, alignment-baseline supports the new keywords alphabetic, ideographic, central, mathematical, and hanging, extending the variety of baselines to choose for alignment.
• Implemented the new popover=hint spec, which removes a series of inconsistent and unexpected behaviors.
• The circle() and ellipse() functions accept two new keywords closest-corner and farthest-corner for their radial size.
• The newly added Error.stackTraceLimit property allows to set the maximal depth of the captured JavaScript error stack as a performance optimization.
• Developers can now use the text import attribute to import text files using the module system.
• The Picture In Picture API exposes a way for web developers to make use of user agent Picture-In-Picture functionality.
• The Intl.LocaleInfo proposal adds the ability to query Locale information, such as week data (first day in a week, weekend start day, weekend end day), text direction and hour cycle used in the Locale.
• The MediaCapabilities.decodingInfo() and MediaCapabilities.encodingInfo() methods now accept the "webrtc" configuration type. This allows a site to query whether a given audio or video configuration can be decoded or encoded for WebRTC and whether doing so will be smooth and/or powerEfficient.

New

• High Dynamic Range (HDR) video playback is now available on Windows - this feature needs HDR mode enabled for the display in Windows Settings - Display. Laptop displays that only offer "HDR video streaming" are not supported at this time. Some videos recorded on phones in certain orientations are currently not shown as HDR.
• Containers let you keep separate parts of your online life (work, shopping, personal, banking) logged into different accounts in the same browser window, but keep your cookies and ad tracking isolated inside each container.
• It is now possible to merge multiple PDFs by dragging a PDF into the PDF sidebar.
• It is now possible to add images as new pages within PDFs using the Firefox PDF editor.
• Quickly pick and copy a color from any page by typing "pick color", "color picker", or "eyedropper" in the address bar and selecting the "Pick a color" quick action.
• Added support for Apple's system-wide full-screen keyboard command (Globe-F).
• Share any open page with a QR code. Right-click a tab, select Share > Generate QR Code. Great for posters, invitations, banners, and other printed materials. On macOS, you can also right-click the address bar to access the Share menu.
• Firefox now verifies and displays Qualified Website Authentication Certificates (QWACs) in accordance with eIDAS regulations.
• Added improved support for videos with overlays so users can more easily access video actions from context menus.
• Firefox now highlights the location permission icon in red whenever a website has access to your location. The permission icon is also now visible on search results pages where it was previously hidden.

Firefox Labs

• Firefox Labs can now be opened quickly by typing "labs" or "experiment" in the address bar and selecting the Open Firefox Labs quick action.
• Firefox now offers experimental support for the new JPEG XL image format, which generally provides better compression than WebP, JPEG, PNG, and GIF and is designed to supersede them. You can enable it from the Firefox Labs panel in Settings.

Changed

• Extensions can no longer access local files by default. Users can grant or revoke this access via the new "Access local files on your computer" permission, separate from "Access your data for all websites".
• Local Network Access restrictions are now enabled by default for all users. Firefox requires websites to request permission before connecting to devices on your local network or to apps and services on your device.
• Outdated cookie settings have been removed from the Settings UI. Users still in that mode should switch to default behavior "Isolate cross-site cookies". More information

Developer

• Developer Information
• A new "Local Mode" setting in the options panel allows developers to load local directories via custom origins. This simplifies testing for APIs that do not function over standard file:// URLs, removing the need to run a local web server. Multiple directory mappings are supported.

Web Platform

• Firefox now supports a limited subset of the non-standard ::-webkit-scrollbar pseudo-element to improve web compatibility:
• Rules with non-zero width/height disable overlay scrollbars for the affected container.
• display: none on ::-webkit-scrollbar behaves like scrollbar-width: none, hiding the scrollbar.
• @supports selector(::-webkit-scrollbar) now evaluates to true.
• Full styling capabilities (colors, border-radius, etc.) are intentionally not supported.
• Updated HTML parsing rules for elements, aligning with web standards to support future customizable select dropdown features.
• The vertical-align property was converted into a shorthand for baseline-source, alignment-baseline, and baseline-shift in Firefox 149. Now, alignment-baseline supports the new keywords alphabetic, ideographic, central, mathematical, and hanging, extending the variety of baselines to choose for alignment.
• Implemented the new popover=hint spec, which removes a series of inconsistent and unexpected behaviors.
• The circle() and ellipse() functions accept two new keywords closest-corner and farthest-corner for their radial size.
• The newly added Error.stackTraceLimit property allows to set the maximal depth of the captured JavaScript error stack as a performance optimization.
• Developers can now use the text import attribute to import text files using the module system.
• The Picture In Picture API exposes a way for web developers to make use of user agent Picture-In-Picture functionality.
• The Intl.LocaleInfo proposal adds the ability to query Locale information, such as week data (first day in a week, weekend start day, weekend end day), text direction and hour cycle used in the Locale.
• The MediaCapabilities.decodingInfo() and MediaCapabilities.encodingInfo() methods now accept the "webrtc" configuration type. This allows a site to query whether a given audio or video configuration can be decoded or encoded for WebRTC and whether doing so will be smooth and/or powerEfficient.

New

• High Dynamic Range (HDR) video playback is now available on Windows - this feature needs HDR mode enabled for the display in Windows Settings - Display. Laptop displays that only offer "HDR video streaming" are not supported at this time. Some videos recorded on phones in certain orientations are currently not shown as HDR.
• Containers let you keep separate parts of your online life (work, shopping, personal, banking) logged into different accounts in the same browser window, but keep your cookies and ad tracking isolated inside each container.
• It is now possible to merge multiple PDFs by dragging a PDF into the PDF sidebar.
• It is now possible to add images as new pages within PDFs using the Firefox PDF editor.
• Quickly pick and copy a color from any page by typing "pick color", "color picker", or "eyedropper" in the address bar and selecting the "Pick a color" quick action.
• Added support for Apple's system-wide full-screen keyboard command (Globe-F).
• Share any open page with a QR code. Right-click a tab, select Share > Generate QR Code. Great for posters, invitations, banners, and other printed materials. On macOS, you can also right-click the address bar to access the Share menu.
• Firefox now verifies and displays Qualified Website Authentication Certificates (QWACs) in accordance with eIDAS regulations.
• Added improved support for videos with overlays so users can more easily access video actions from context menus.
• Firefox now highlights the location permission icon in red whenever a website has access to your location. The permission icon is also now visible on search results pages where it was previously hidden.

Firefox Labs

• Firefox Labs can now be opened quickly by typing "labs" or "experiment" in the address bar and selecting the Open Firefox Labs quick action.
• Firefox now offers experimental support for the new JPEG XL image format, which generally provides better compression than WebP, JPEG, PNG, and GIF and is designed to supersede them. You can enable it from the Firefox Labs panel in Settings.

Changed

• Extensions can no longer access local files by default. Users can grant or revoke this access via the new "Access local files on your computer" permission, separate from "Access your data for all websites".
• Local Network Access restrictions are now enabled by default for all users. Firefox requires websites to request permission before connecting to devices on your local network or to apps and services on your device.
• Outdated cookie settings have been removed from the Settings UI. Users still in that mode should switch to default behavior "Isolate cross-site cookies". More information

Developer

• Developer Information
• A new "Local Mode" setting in the options panel allows developers to load local directories via custom origins. This simplifies testing for APIs that do not function over standard file:// URLs, removing the need to run a local web server. Multiple directory mappings are supported.

Web Platform

• Firefox now supports a limited subset of the non-standard ::-webkit-scrollbar pseudo-element to improve web compatibility:
• Rules with non-zero width/height disable overlay scrollbars for the affected container.
• display: none on ::-webkit-scrollbar behaves like scrollbar-width: none, hiding the scrollbar.
• @supports selector(::-webkit-scrollbar) now evaluates to true.
• Full styling capabilities (colors, border-radius, etc.) are intentionally not supported.
• Updated HTML parsing rules for elements, aligning with web standards to support future customizable select dropdown features.
• The vertical-align property was converted into a shorthand for baseline-source, alignment-baseline, and baseline-shift in Firefox 149. Now, alignment-baseline supports the new keywords alphabetic, ideographic, central, mathematical, and hanging, extending the variety of baselines to choose for alignment.
• Implemented the new popover=hint spec, which removes a series of inconsistent and unexpected behaviors.
• The circle() and ellipse() functions accept two new keywords closest-corner and farthest-corner for their radial size.
• The newly added Error.stackTraceLimit property allows to set the maximal depth of the captured JavaScript error stack as a performance optimization.
• Developers can now use the text import attribute to import text files using the module system.
• The Picture In Picture API exposes a way for web developers to make use of user agent Picture-In-Picture functionality.
• The Intl.LocaleInfo proposal adds the ability to query Locale information, such as week data (first day in a week, weekend start day, weekend end day), text direction and hour cycle used in the Locale.
• The MediaCapabilities.decodingInfo() and MediaCapabilities.encodingInfo() methods now accept the "webrtc" configuration type. This allows a site to query whether a given audio or video configuration can be decoded or encoded for WebRTC and whether doing so will be smooth and/or powerEfficient.