Firefox 128 for developers

This article provides information about the changes in Firefox 128 that affect developers. Firefox 128 is the current Nightly version of Firefox and ships on July 9, 2024.

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

  • The default value of proxy.settings property proxyDNS is now false when using SOCKS4 and true when using SOCKS5. Previously, it defaulted to false for SOCKS4 and SOCKS5 (Firefox bug 1741375).

Removals

Other

Experimental web features

These features are newly shipped in Firefox 128 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