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See what landed recently in Firefox Nightly!

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.

133.0a1 Firefox Nightly

September 30, 2024

Version 133.0a1, first offered to Nightly channel users on September 30, 2024

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 X 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 chat.mozilla.org.

New

  • Starting with Firefox 129, Firefox Nightly will automatically try to use a secure HTTPS connection whenever possible when loading a page. This behavior is known as "HTTPS-First", or "HTTPS Upgrades", and has been the default in Firefox's private browsing mode since Firefox 91. Here is a blog post from when this feature was introduced in Private Browsing.

    Bug 1719271
  • You can now show tabs from other devices in the Tab overview menu.

    Bug 1901728

Fixed

  • Fix for MFSA 2024-51 included in 2024-10-08 builds and newer.

Changed

  • Starting with Firefox for Android 131, HLS playlist support was deprecated in Nightly builds. Extended testing showed no adverse impact as newer playback technologies have been widely adopted by websites.

    Bug 1911651

Web Platform

  • Starting with Firefox Nightly 131, support for the non-mandatory options argument to getBBox will get the bounding box of the element, including its stroke (e.g. element.getBBox({"stroke": true})). (Learn more)

    Bug 1914182
  • Firefox now supports the keepalive option in the Fetch API. This feature allows developers to make HTTP requests that can continue to run even after the page is unloaded, such as during page navigation or closing.

    Bug 1923044
  • Firefox now supports Permissions API in Worker Context.

    Bug 1193373

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