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.

150.0a1 Firefox Nightly

February 23, 2026

Version 150.0a1, first offered to Nightly channel users on February 23, 2026

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 Bluesky account, our @FirefoxNightly 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 chat.mozilla.org.

New

  • Starting with Firefox 148, Nightly builds have stability improvements to the legacy search bar, as well as aligning its search button with the latest designs.

    Bug 2006632

  • Starting with Firefox 148, the updated Firefox sidebar is now enabled by default for new profiles in Nightly builds. It provides quick access to tools like bookmarks, history, and AI chatbots. Use the settings gear icon at the bottom of the sidebar to add and remove tools, try vertical tabs, or move the sidebar.

    Bug 1978102

  • Starting with Firefox 148, HDR video on Windows is now supported in Nightly builds. This is considered experimental as we gather feedback before enabling it in regular releases. This feature works best when HDR mode is enabled in Display Settings (this may require a page refresh); otherwise, the display driver is likely to apply a tonemapping effect for non-HDR viewing. Some streaming sites may still not offer HDR video in Firefox. (Learn more)

    Bug 1977746

  • Starting with Firefox 149, Firefox Nightly now ships with a new .rpm package for Linux users on Red Hat, Fedora, openSUSE, and other RPM-based distributions.

    Bug 213920

  • Starting with Firefox 149, WebGL/WebGPU is rendered as overlay on Windows if supported.

    Bug 2008399

  • Starting with Firefox 149, we now supports throttling for Web Workers running in inactive tabs. When a tab becomes inactive, Firefox reduces how aggressively its workers can run timeouts.

    Bug 2011100

Changed

  • Starting with Firefox 149, on Windows, Firefox will use the modern Windows.Devices.Geolocation API for geolocation instead of Windows 7 location API.

    Bug 1980653

Developer

Web Platform

  • Starting with Firefox 148, Nightly builds now support the Document Picture-in-Picture API, which allows web pages to place content in an always-on-top popup.

    Bug 1858562

  • Starting with Firefox 148, Nightly builds now open an in-page popup for <input type=color> instead of an OS-dependent color picker. Which means it now shows the same behavior on all desktop platforms.

    Bug 1629388

  • Starting with Firefox 149, you can now set specific color spaces and transparency (alpha) on <input type="color"> elements, with alpha support currently exclusive to Firefox Nightly. While the visual picker hasn't changed yet (tracked in Bug 2007532), it will now output values in your requested format.

    Bug 1919718

  • Starting with Firefox 149, the spec-compliant HTMLMediaElement.captureStream() API is now enabled.

    Bug 2016216

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