Firefox Nightly
Release Notes

Starting with Firefox 127, we're enabling a new anti-tracking feature in Nightly: Bounce Tracking Protection. This protection detects bounce trackers based on redirect behavior and periodically purges their cookies & site data to prevent tracking.

Starting with Firefox for Android 128, the new tab strip feature for tablets is available for testing in Nightly builds! This enhancement makes tab management more intuitive and efficient, providing a smoother browsing experience for devices in that form factor. Please share your feedback on Google Play and/or the Mozilla Connect post to help us improve it further.

Firefox now supports playback of protected content from streaming sites like Netflix while in Private Browsing mode.

Firefox now has a simpler and more unified dialog for clearing user data. In addition to streamlining data categories, the new dialog also provides insights into the site data size corresponding to the selected time range.

Microphone capture through getUserMedia on macOS will use system-provided voice processing when applicable for improved audio quality.

Firefox is now available in the Saraiki (skr) language.

Starting with Firefox 128, hovering the mouse over an unfocused tab will now display a visual preview of its contents in Nightly builds.

Firefox now proxies DNS by default when using SOCKS v5, avoiding leaking DNS queries to the network when using SOCKS v5 proxies.

Deprecated support of HLS playlist support in Firefox for Android.

Firefox now supports rendering more text/* file types inline, rather than requiring them to be downloaded to be viewed.

Starting with Firefox 125, the transition-behavior CSS property is now supported in Nightly builds.

Starting with Firefox 125, Nightly builds will attempt to establish TLS connections using a hybrid post-quantum key agreement mechanism (X25519+Kyber768). This may result in slow TLS handshakes or failed connections on networks with TLS intercepting middleboxes. The feature can be disabled by setting the security.tls.enable_kyber preference to false.

Starting with Firefox 126, the shape() function on clip-path property is now supported in nightly builds.

Starting with Firefox 126, the shape() function on offset-path property is supported in nightly builds.

Starting with Firefox 126, interpolation between path() function and shape() function is now supported in nightly builds.

Starting with Firefox 127, Nightly users now have the ability to translate selections of text from the right-click context menu, rather than only being able to translate the entire web page.

Starting with Firefox 127, the relative color syntax is supported in CSS color functions in Nightly builds. This allows to create colors based on other colors.

Starting with Firefox 127, @starting-style is supported in Nightly builds. This at-rule allows to define styles that are applied to an element when it is first rendered, enabling transitions on elements that are added to the DOM or that have their display type changed from none to another value.

The setCodecPreferences method allows applications to disable the negotiation of specific codecs (including RTX/RED/FEC). It also allows an application to cause a remote peer to prefer the codec that appears first in the list for sending.

The Accept header for images and documents was changed to better align with the Fetch standard and other browsers.

Firefox now supports @property and the CSS properties-and-values API.

Starting with Firefox 128, Firefox Nightly now has initial support for the CHIPS (Cookies Having Independent Partitioned State) standard.

Resizeable ArrayBuffers and Growable SharedArrayBuffers are now supported in SpiderMonkey. This allows the size of an ArrayBuffer to be changed without having to allocate a new buffer and copy data into it.