Add-on Compatibility for Firefox 46

Firefox 46 will be released on April 19th 26th. Here’s the list of changes that went into this version that can affect add-on compatibility. There is more information available in Firefox 46 for Developers, so you should also give it a look.



  • Firefox is currently enforcing add-on signing, with a preference to override it. Firefox 46 will remove the preference entirely , which means your add-on will need to be signed in order to run in release versions of Firefox. You can read about your options here.


Let me know in the comments if there’s anything missing or incorrect on these lists. If your add-on breaks on Firefox 46, I’d like to know.

The automatic compatibility validation and upgrade for add-ons on AMO will happen in a few weeks (the one for Firefox 45 is still pending), so keep an eye on your email if you have an add-on listed on our site with its compatibility set to Firefox 45.

10 comments on “Add-on Compatibility for Firefox 46”

  1. Kohei Yoshino wrote on

    Posted my Japanese translation:

    1. Jorge Villalobos wrote on


  2. IByte wrote on

    Mandatory add-on signing is unacceptable to me. I guess I’ll switch to Developer Edition.

  3. dal wrote on

    welp, guess i’m staying with my old, outdated version, then moving to chrome when its’ no longer secure.

    or perhaps y’all can stop pussyfooting around with “this nevt one will be all mandatory, honest!” like you’ve been since 41, and just make it a permanent feature already. Go and look at the vast swathe of comments, people hate being told what they can and can’t do with their own system, and people who fork projects are stuck out in the cold. give it up already

  4. Chris Parker wrote on

    When will electrolysis be forced on for addons? The wiki page says that for 46 beta, e10s is 50-50 (addons & a11y = off). Does that mean that electrolysis is definitely off for addons in 46?

    Will there be an opt in time for addons or will there be a strict cutover version?

    Thanks for the information.

    1. Jorge Villalobos wrote on

      It will definitely be off for add-ons in 46. I think the current target is around Firefox 48. When it’s clear which version will be enabled for profiles with add-ons, we will start marking affected add-ons as incompatible, so there will be no opt-in transition.

      1. Chris Parker wrote on

        Marking them in the AMO? What about unlisted add-ons?


        1. Jorge Villalobos wrote on

          We could mark unlisted add-ons as incompatible as well, but they would be lower priority for this. We also wouldn’t want to hold unlisted add-ons to the same standard as listed ones.

  5. Natalie wrote on

    We were promised an unbranded Firefox in which we could continue to disable mandatory signing. When and where do we get that?

    1. Jorge Villalobos wrote on

      My understanding is that the preference will be removed in one of the following betas for 46, and the unbranded builds will become available at that time.