Firefox 141 for developers

This article provides information about the changes in Firefox 141 that affect developers. Firefox 141 is the current Nightly version of Firefox and ships on July 22, 2025.

Changes for web developers

Developer Tools

HTML

Removals

CSS

Removals

JavaScript

Removals

SVG

Removals

HTTP

Removals

Security

Removals

APIs

DOM

Media, WebRTC, and Web Audio

Removals

WebAssembly

Removals

WebDriver conformance (WebDriver BiDi, Marionette)

General

WebDriver BiDi

Marionette

Changes for add-on developers

Removals

Other

Experimental web features

These features are shipping in Firefox 141 but are disabled by default. To experiment with them, search for the appropriate preference on the about:config page and set it to true. You can find more such features on the Experimental features page.

Older versions