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Firefox Nightly
Release Notes

Release Notes tell you what’s new in Firefox. As always, we welcome your feedback. You can also file a bug in Bugzilla or see the system requirements of this release.

122.0a1 Firefox Nightly

November 20, 2023

Version 122.0a1, first offered to Nightly channel users on November 20, 2023

Firefox Nightly gets updated every day and as a consequence, the release notes for the Nightly channel are updated continuously to reflect features that have reached sufficient maturity to benefit from community feedback and bug reports.

Warning: Features listed here may or may not make a final release of Firefox.

In addition to these release notes, you can follow ongoing development on our @FirefoxNightly Twitter account, our Mastodon account as well as read our Nightly Blog.

You can interact with other Firefox Nightly users and give your feedback to Mozilla staff in the Nightly Matrix room on


  • Firefox for Android can now be set as the default PDF reader.

    Bug 1815739
  • Starting with Firefox 122, the URL Paste Suggestion feature is now enabled by default in Nightly builds. This enhancement provides a convenient way for users to quickly visit URLs copied to the clipboard in the address bar of desktop Firefox. When the clipboard contains a URL, and the user focuses on the URL bar, an autocomplete result appears automatically. Activating the clipboard suggestion will navigate the user to the URL with 1 click.

    Bug 1860548
  • Starting with Firefox 122, scroll animations triggered using a mouse wheel or using the keyboard (e.g. arrow keys, Page Down/Up) are now based on a Mass-Spring-Damper physics model in Nightly builds, this gives animations a more realistic feel.

    Bug 1846935
  • Firefox now displays images and descriptions for search suggestions when provided by the search engine.

    Bug 1867375
  • Starting with Firefox 122, it is now possible to highlight information in the Firefox PDF viewer in Nightly builds.

    Bug 1867512
  • Firefox for Android now supports enabling Global Privacy Control. With this feature, Firefox informs the websites that the user doesn’t want their data to be shared or sold. This feature is enabled in private browsing mode by default and can be enabled in normal browsing in Settings → Enhanced Tracking Protection -> Tell websites not to share & sell data toggle.

    Bug 1865357
  • Firefox now supports creating and using passkeys stored in the iCloud Keychain on macOS.

    Bug 1869374
  • The line breaking rules of Web content now match the Unicode Standard. This improves Web Browser compatibility for line breaking.

    An additional improvement for East Asian and South East Asian end users, Firefox now supports proper language-aware word selection when double-clicking on text, for languages including Chinese, Japanese, Burmese, Lao, Khmer, and Thai.

    Bug 1854032
  • The translations feature received an improvement to the quality of translated webpages. The results should be much more stable. This fixes issues where the content of a page could disappear when translated, or interactive widgets could break.

    Bug 1837424

Web Platform

  • Starting with Firefox 120, ULPFE/RED is now on by default for video in Nightly builds. This provides additional protection against packet loss for video during WebRTC calls.

    Bug 1852837
  • Firefox now supports animating the SVG viewBox attribute using SMIL by animations. by animations are animations that are relative to the original value. Other attributes such as lengths and angles already support by, but a viewBox consists of four separate values.

    Bug 1865470
  • The LargestContentfulPaint API has been added, this provides timing information about the largest image or text paint before users interact with a web page.

    Bug 1866266
  • <hr>-in-<select> is now supported, allowing websites to easily use separators inside a <select> element.

    Bug 1830909
  • Starting with Firefox 122, the popover attribute is now supported by default in Nightly builds. The popover global attribute is used to designate an element as a popover element. The element won't render until it becomes shown, it will then render on top of other page content.

    Bug 1866666
  • The showPicker method is now supported on <select> elements, this can be used to trigger the drop-down behavior via JavaScript.

    Bug 1865207
  • The fallback URL parser for unknown schemes was changed to DefaultURI this improves specification adherence and web compatibility.

    Bug 1603699
  • Added support for ray() to the offset-path CSS property.

    Bug 1598151
  • Enabled the offset-position property which is useful for most of the offset-path values.

    Bug 1598152
  • Added support for basic-shape and coord-box for the offset-path CSS property.

    Bug 1598159
  • Starting with Firefox 122, the remaining part of the async clipboard API has been enabled by default in Nightly builds. A paste context menu will appear for the user to confirm when attempting to read clipboard data not provided by the same-origin page.

    Bug 1809106
  • Enabled the ArrayBuffer.prototype.transfer proposal methods, which enables transferring ownership of ArrayBuffer data.

    Bug 1865103
  • Added support for rect() and xywh() basic shapes on clip-path and offset-path CSS properties.

    Bug 1868722
  • Starting with Firefox 122, support for the Screen Wake Lock API is available in Nightly builds.

    Bug 1589554
  • Starting with Firefox 122, Nightly builds include support for Unicode text segmentation to JavaScript.

    Bug 1423593
  • Firefox now recognizes the "webauthn" autocomplete token and will suggest passkeys in form autofill dialogs.

    Bug 1864541
  • Scripts can now store cacheAPI data in Private Browsing mode. Previously, user experience for someone browsing in private browsing mode could be significantly different than in regular mode. With these changes, websites can store cacheAPI data in Private Mode moving towards a uniform experience in regular vs Private Browsing mode.

    Bug 1864684
  • To further protect user privacy Firefox now taints filters that use currentColor as an input. Since color can be set by the :visited pseudo selector, it potentially contains privacy-sensitive information and therefore these primitives must be marked as tainted. This means that if you use such a filter you won't be able to read the filter output from canvas.

    Bug 1869202


  • Some machines with older AMD CPUs may see image thumbnails incorrectly render as all black in file dialogs. If this is the case, updating the graphics driver should address this issue.

    Bug 1328838

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All Firefox Nightly downloads