A couple of months ago, we shared an update on our Cache the World project, covering the ongoing re-write of the Firefox accessibility engine. The project aims to improve Firefox’s overall performance for users of assistive technologies (ATs) like screen readers and to reduce crashes and hangs. It will also make the accessibility engine easier to maintain and simplify adding new features going forward.

In our last post, we provided instructions for enabling the new engine in Firefox Nightly by changing an experimental setting and encouraged adventurous Windows OS users to opt in and try it out. Thanks to your testing and feedback, and further work by the engineering team, the new Firefox accessibility engine is now solid enough that we have enabled it for all Firefox Nightly users, starting with the Nightly build on November 15th (id: 20221115095444 or newer). Unless you’ve changed Firefox’s update settings, it will attempt to automatically update twice per day, but you can perhaps speed that up by manually checking for updates. To do that, navigate to the Firefox menu, then to Help, and then to About Nightly. Alternatively, open the Help menu from the Windows menu bar and choose About Nightly. That will do an update check; if an update is available Firefox will download it. After a restart to finish the update, Firefox will be using the new accessibility engine.

We’ve enabled this in Nightly so that we can gather more feedback, both from AT users, as well as from non-AT users or users who may not know Firefox’s accessibility engine has been activated due to an OS feature or third party application. We believe that the experience for most Nightly screen reader users will be a significant improvement over the old engine, as many of you have told us after opting in to the Nightly preview. As well as direct feedback we receive, enabling it by default in Nightly will allow us to gather automatic feedback via crash reports. We will also be receiving feedback from a larger group of users with more diverse use cases which will help us move closer to a beta release and an eventual release to the full Firefox audience.

If you experience slow-downs, more frequent crashes, or missing capabilities that prevent you from using Firefox Nightly as you normally would, you can revert to the old accessibility engine by going to Firefox Settings, entering accessibility cache into the search box, tabbing to the Accessibility cache check box and turning it off. After a restart, you’ll be back on the old engine. If this does become necessary or you have any other feedback to offer, please file a Bugzilla report or stop in at our Matrix chat and let us know.