Firefox 107 for developers

This article provides information about the changes in Firefox 107 that will affect developers. Firefox 107 was released on November 15, 2022.

Changes for web developers


No notable changes


  • Deprecated lquote and rquote attributes of the <ms> MathML element for custom opening and closing quotes are now disabled. This behavior is configured via the mathml.ms_lquote_rquote_attributes.disabled preference which is set to true by default (Firefox bug 1793387).



No notable changes



WebDriver conformance (WebDriver BiDi, Marionette)

WebDriver BiDi

  • Added Realm support to target argument for script.evaluate, script.callFunction, and script.disown commands (Firefox bug 1779231).
  • Added support for JSON serialization of complex objects with container value fields, eg. WeakMap and Uint8Array (Firefox bug 1770754).
  • Added support for the context parameter of the browsingContext.create command, which allows opening a new tab related to an existing one (Firefox bug 1765619).
  • Improved reliability of the browsingContext.navigate command when called with the wait parameter set to none (Firefox bug 1763109).


  • The command WebDriver:ElementSendKeys now only sets the caret if the element is not focused yet (Firefox bug 1791736).
  • Updated the command WebDriver:PerformAction to no longer accept undefined as value for various parameters of the pointerMove and wheel actions (Firefox bug 1781066).
  • Updated the Selenium Atoms to match a recent WebDriver specification change (Firefox bug 1771942).

Changes for add-on developers


  • The error property returned when an error occurs in scripting.executeScript now represents any value the script throws or rejects with, instead of being just an object with a message property Firefox bug 1740608.

Older versions