Firefox 89 for developers

This article provides information about the changes in Firefox 89 that will affect developers. Firefox 89 was released on June 1, 2021.

Note: See also Looking fine with Firefox 89 on Mozilla Hacks.

Changes for web developers

Developer Tools

No changes.

HTML

No changes.

CSS

JavaScript

HTTP

No changes.

APIs

DOM

Removals

  • The following sensor events and their associated handlers have been removed (primarily for better compatibility with other major browser engines, and to address concerns related to privacy leaks):

WebDriver conformance (Marionette)

Removals

  • The rotatable capability that is not part of the WebDriver specification is no longer used (Firefox bug 1697630).

Changes for add-on developers

Older versions