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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.

86.0a1 Firefox Nightly

December 15, 2020

Version 86.0a1, first offered to Nightly channel users on December 15, 2020

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 as well as read our Nightly Blog.


  • Expanding credit card management and autofill capabilities to Canadian builds of Firefox

    Bug 1676875
  • Enable multiple Picture-in-Picture support by default

    Bug 1687477


  • Reader mode now works with local HTML pages.

    Bug 1166829


  • To prevent user data loss when filling out forms, we’ve disabled the Backspace key as a navigation shortcut for the back navigation button. To re-enable the Backspace keyboard shortcut, you can change the about:config preference browser.backspace_action to 0. You can also use the recommended Alt + Left arrow (Command + Left arrow on Mac) shortcut instead.
    Firefox keyboard shortcuts

    Bug 1041377

Web Platform

  • Basic AVIF support is enabled in Firefox 86. Some advanced features like animated images and colorspace support are still in development (see bug 1443863 and dependencies)

    Bug 1682995

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All Firefox Nightly downloads