Firefox 109 for developers

This article provides information about the changes in Firefox 109 that will affect developers. Firefox 109 is the current Nightly version of Firefox and will ship on January 17, 2023.

Changes for web developers

Developer Tools

HTML

Removals

CSS

Removals

JavaScript

Removals

HTTP

Removals

Security

Removals

APIs

DOM

Media, WebRTC, and Web Audio

Removals

WebAssembly

Removals

WebDriver conformance (WebDriver BiDi, Marionette)

WebDriver BiDi

Marionette

Changes for add-on developers

Removals

Other

Older versions