My Addons

Firefox Nightly (will be 56) already no longer supports addons which are not multiprocess-compatible. And Firefox 57 will not support “Legacy” addons – those which use XUL, XPCOM or the Addons SDK. I just started using Nightly instead of Aurora as my main browser, at Mark Mayo’s request :-), and this is what I found (after doing “Update Addons”):

  • Addons installed: 37
  • Non-multiprocess-compatible addons (may also be marked Legacy): 21 (57%)
  • Legacy addons: 5 (14%)
  • Addons which will work in 57, if nothing changes: 11 (29%)

Useful addons which no longer work as of now are: 1-Click YouTube Video Downloader, Advertising Cookie Opt-Out, AutoAuth, Expiry Canary (OK, I wrote that one, that’s my fault), Google Translator, Live HTTP Headers, Mass Password Reset, RESTClient, and User Agent Switcher.

Useful addons which will also no longer work in 57 (if nothing changes) include: Adblock Plus, HTTPS Everywhere, JSONView, and Send to Kodi.

I’m sure Adblock Plus is being updated, because it would be sheer madness if we went ahead and it was not being. As for the rest – who knows? There doesn’t seem to be a way of finding out other than researching each one individually.

In the Firefox (I think it was) Town Hall, there was a question asked about addons and whether we felt that we were in a good place in terms of people not having a bad experience with their addons stopping working. The answer came back that we were. I fully admit I may not be a typical user, but it seems like this will not be my experience… :-(

11 thoughts on “My Addons

  1. For JSONView, try the internal json viewer which is also enabled by default in release. It’s a similar situation regarding addon compatibility with Firefox 57 here.


    I can’t find what the ad cookie opt-out add-on is (as in, I can’t find an add-on with that name using google), but it sounds like it should be available/implementable as a webextension? HTTPS Everywhere also already has a webextension version (which they use in Chrome) – it seems there are some technical details about update signing which are stopping them from putting this on AMO today ( ) but you should be able to switch easily.

    It seems the developer of live http headers thinks you can just use the devtools as they ship with Firefox (see comments on AMO).

  3. Providing a list of alternatives or extensions updated for webx is not the point.

    The point is simply that come FF 57 (or even 56) many extensions simply will not work when the user starts up their browser.


    That is a very poor UX.

    So if you’re looking to maintain, or gain, users, well…

  4. Just checked my installed addons. Of the 14 addons i have installed and enabled 1 is not marked “Legacy”. So I guess 13 out of 14 will stop working. Not good.

  5. 12 out of 24 of my addons are “Legacy”, and that’s after several months of attempting to find WebExtension replacements. From what I gather, many of the remainder can’t upgrade because of poor progress on the API front (aside from those that flat out will never work).

    I expect the “everything’s going great!” crowd to start looking very uncomfortable in a month or so.

  6. Yes, Adblock Plus is going to be updated. However, I am all but impressed with the quality of our test builds – and only part of the issues is our fault. In fact, I’m all but impressed with the quality of our current release which is merely using Web Extensions for I/O (this is necessary to migrate data). So we will delay the Web Extensions release as much as possible.

  7. An extended ContentBlocker should become part of FF itself so all external sources need to maintain is scriptlets and filter rules.

    Meanwhile, you could also switch to UblockOrigin by Raymond Gorhill who already made his extension compatible and will soon push it to AMO

  8. Although you may not be a typical user your experience with this switch to WebExtensions should be a warning for the people forcing this switch. In my opinion they should at least ensure that the switch is done in tandem with a release of a Long Term Support Firefox (which then gives users a possibility to keep using their classic extensions for about a year after the classic XUL/XPCOM have been forced out the normal Firefox codebase).

    To me this experience you have indicates that the Mozilla developers clearly are not as close in touch with the extension developers as should be needed. When 70% of the add-ons of the average user no longer work after upgrading to Fx 57 somewhere in the planning of the deprecation something went wrong.

    Also the comment made by Wladimir Palant related to the stability of WebExtensions are also not very encouraging.

    Today I noticed a complaint about missing features in WebExtensions on Cameron Kaiser’s blog (

    Somehow all comments I (and possibly others) made related to feature completeness of WebExtensions vs XPCOM/XUL seem to be have fallen on deaf ears when it comes to the people responsible for the add-on/extension logic.

    @Gerv: Hopefully your experience will be a wake-up call for the developers & managers responsible for this. I would personally appreciate it if you could discuss at least the part related to changing the switch moment to be just after another Long Term Support Firefox has been releases. (which I already said when commenting on the add-ons blog when it comes to this switch).

    I would also help if the WebExtension-logic would be feature complete with at least the top 25 add-ons used at the moment. (Which should be relatively easy to check based on the stats from amo).

    What to me also is not a sign of good PR is that the WebExtension logic is not even designed in a way that add-ons which are created as a response of removing logic from Firefox (as is the case with gopher support in case on Cameron’s add-on). While gopher support may be of the past (at least to me as I never used it :-) ), it is even more a slap in the face of the developer who created the Tab Groups extension as a response in removal of this feature from Firefox. As far as I know there is no way to get this extension ported to WebExtension because of mmissing logic.

  9. When 70% of the add-ons of the average user no longer work

    I am not the average user. The average user doesn’t have any extensions. The average user with extensions only has one or two.

    While it’s not good that people like me get a bad experience, because we are often the people who promote and recommend Firefox, you cannot take my experience and then assume it will be the experience of the average person.

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