Add-ons Update – Week of 2015/11/25

I post these updates every 3 weeks to inform add-on developers about the status of the review queues, add-on compatibility, and other happenings in the add-ons world.

The Review Queues

In the past 3 weeks, 758 add-ons were reviewed:

  • 602 (79%) were reviewed in less than 5 days.
  • 32 (4%) were reviewed between 5 and 10 days.
  • 124 (16%) were reviewed after more than 10 days.

There are 281 listed add-ons awaiting review, and 189 unlisted add-ons awaiting review. I should note that this is an unusually large number of unlisted add-ons, which is due to a mass uploading by a developer with 100+ add-ons.

Review times for most add-ons have improved recently  due to more volunteer activity. Add-ons that are admin-flagged or very complex are now getting much needed attention, thanks to a new contractor reviewer. There’s still a fairly large review backlog to go through.

If you’re an add-on developer and would like to see add-ons reviewed faster, please consider joining us. Add-on reviewers get invited to Mozilla events and earn cool gear with their work. Visit our wiki page for more information.

Firefox 43 Compatibility

This compatibility blog post is now public. The bulk compatibility validation should be run soon.

As always, we recommend that you test your add-ons on Beta and Firefox Developer Edition to make sure that they continue to work correctly. End users can install the Add-on Compatibility Reporter to identify and report any add-ons that aren’t working anymore.

Changes in let and const in Firefox 44

Firefox 44 includes some breaking changes that you should all be aware of. Please read the post carefully and test your add-ons on Nightly or the newest Developer Edition.

Extension Signing

The wiki page on Extension Signing has information about the timeline, as well as responses to some frequently asked questions. The current plan is to turn on enforcement by default in Firefox 43.


Electrolysis, also known as e10s, is the next major compatibility change coming to Firefox. In a nutshell, Firefox will run on multiple processes now, running content code in a different process than browser code.

This is the time to test your add-ons and make sure they continue working in Firefox. We’re holding regular office hours to help you work on your add-ons, so please drop in on Tuesdays and chat with us!

Web Extensions

If you read the post on the future of add-on development, you should know there are big changes coming. We’re investing heavily on the new WebExtensions API, so we strongly recommend that you start looking into it for your add-ons. You can track progress of its development in

4 responses

  1. Chaofan Wu wrote on :

    Hi, I want to know if extension signing is an enforcement in Firefox 45 ESR and if e10s will be integrated into Firefox 45 ESR because we track Firefox ESR release.

    1. Jorge Villalobos wrote on :

      The current plan for ESR is that it will behave like 43, where it will have the signing enforcement preference turned on by default, but can be switched off. For e10s, given the current schedule, I’d be surprised that it makes it to 45. Currently, only a subset of Beta 44 users will be using Firefox with e10s on, so making it to release on 45 would mean that everything worked exceptionally well.

      1. Chaofan Wu wrote on :

        Thanks, so legacy extension based on XUL can still work on Firefox 45 with e10s off, right?

        1. Jorge Villalobos wrote on :

          Yes. Dropping legacy XUL extensions is still fairly far in the future.