Add-on Compatibility for Firefox 23

Firefox 23 will be released on August 6th. Here’s the list of changes that went into this version that can affect add-on compatibility. There is more information available in Firefox 23 for Developers, so you should read that too.



  • URI_SAFE_FOR_UNTRUSTED_CONTENT can’t be used in privileged about: pages. If your add-on includes a custom about: page, you can’t use this flag anymore if you also want to use XUL or access privileged code from it.
  • Form history should use asynchronous storage API. The sanitize function in the Sanitizer object now returns a promise instead. Also, using autoCompleteSearch should be replaced by autoCompleteSearchAsync, which can be found in resource://gre/modules/FormHistory.jsm.
  • Can’t un-set the clicktoplay flag on an nsIPluginTag. This makes nsIPluginTag.disabled and nsIPluginTag.clicktoplay readonly now.
  • Clean up nsISidebar. This changes most of the nsISidebar and nsISidebarExternal interfaces. You can see the diff here.


Please let me know in the comments if there’s anything missing or incorrect on these lists. If your add-on breaks on Firefox 23, I’d like to know.

The automatic compatibility validation and upgrade for add-ons on AMO will happen in the coming week or so, so check your email if you have an add-on listed on our site with Firefox 22 compatibility.

19 comments on “Add-on Compatibility for Firefox 23”

  1. Ommrudraksha wrote on

    In the last few updates, i found one or two add ons from my long list of add ons to not be working with the new version.

    1. Alex wrote on

      Check if it’s related to this: . I hope 23 will sort this out!

  2. Luke wrote on

    Thanks, but I was wondering why the list here only lists one of these changes?

    Also why does the page say “New features will be added to it in the near future.” if this is beta that will be released in a little over a week?

    1. Jorge Villalobos wrote on

      The list on MDN is written by others, which is why both lists are often different. The “New features” note is outdated also. “Feature freeze” effectively happens when a version is pushed to the beta channel. After that, only critical bugs are fixed.

  3. Felix wrote on

    My add-on breaks because I’m inserting iframes with a custom protocol into pages. The only purpose of the custom protocol is to prevent the page from accessing the (user generated) content that I’m inserting. Is there a way to “mark” custom protocols as secure or to always allow the connection to a specific URL? All I’m loading is an HTML template (which is part of the add-on). The main purpose of the URL is to enforce the same-origin policy. Thanks for your help!

    1. Jorge Villalobos wrote on

      I recommend that you ask either on the #extdev channel on Mozilla’s IRC Network, or in the Add-ons Forum.

  4. Nicholas Bodley wrote on

    As a moderately-technical user, I’m horrified! Old favorite add-ons have disappeared, or are incompatible. Granted, you probably had to improve security, but almost every add-on
    in your online list is incompatible. I tried downloading six or so, all apparently compatible according to the list. After download, all were incompatible. What this means in practical terms is that Ffx can have no useful add-ons in the near future. Finding one that works is simply not worth the effort at all.

    I’m using a Nexus 7 2B16 / FHD, with the latest version of Android.

    Firefox has been my favorite browser for years.
    I do hope that you don’t lose in the ongoing competition.

  5. Nicholas Bodley wrote on

    I have several hundred, maybe > 1,000 bookmarks, arranged in nested folders. Ffx 23 shows them as one huge flat listing, which is almost totally useless. I have a crying need for restoring my hierarchical structure! The list is much too long to scroll through.

    So many add-ons are no longer listed, or incompatible, it’s well… just tragic. I’m going to try the current Opera for mobile.
    Currently using 2013 Nexus 7.
    Thanks for posting my previous comments.

  6. Carol wrote on

    I have used Firefox for quite a few years and since Firefox 23 my Windows freezes. Each time I have attempted to open my Favorites I see at the top of the page a new toolbar not recognizable and must have come with FF 23. Could the toolbar be what is freezing my Window?
    I’m using Internet Explorer until reading something “simple” I can do to fix the freezing problem.

    1. Carol wrote on

      Just to clarify – I work from the Menu Bar no matter what I open in FF 23 it will freeze. Favorites in IE works fine. Thank you for your consideration in this matter.

  7. Nicholas Bodley wrote on

    Since my last post, I discovered the current Ffx Android add-ons collection. All the old ones are gone, but there are good new ones, and I installed a good number of them. The current add-on pages have small text that tells which versions of Ffx are compatible with each add-on.

    What amazes me is that Web searches about huge changes to Ffx 23 add-on compatibility yield /no/ hits, using several browsers! This is downright creepy, as if Mozilla had gained total control over Web search results, at least on Android devices. That’s paranoid, and hard to believe; I’m utterly baffled — mystified.

    Mozilla appears to be tightening up security a lot, making many changes. While there’s temporary grief, it will be good in the long run.

  8. Karen wrote on

    All of my addon’s have disappeared. This is not acceptable! Really! I use my addon’s every day and now they are gone. I have tried to reinstall them but after installation is done, Firefox locks up and I have to shut it down using the task manager. After I restart Firefox, all of the addons have vanished again.

    This is ridiculous – I am going to try to go back to an older, portable version. I can’t work this way…

    1. Jorge Villalobos wrote on

      Please visit our support site for help.

  9. ‘Nicabod’ wrote on

    Although I didn’t expect much, I went to the support pages. My tablet is not rooted, so I couldn’t check Ffx extension files as was recommended for Windows. Quite likely that essestially all traditional add-ons are incompatible, so this was just spinning my wheels. When asked whether the support was helpful, I said it wasn’t. I entered text for a report, but it was not accepted and asked for more details. I had given some specifics, but added Nexus 7 2, Android 4.3, Build JSS15Q. Still asked for more details. Gave up. Assumed that the text I entered was parsed as too subjective. I didn’t use any abusive language.


    Support pages are for desktop, can’t be expanded by a two-finger stretch, and fortunately one of my eyes is nearsighted, or else I would have needed a third hand to hold a magnifier. Text was perhaps 2 point!


    I recently read the remarkable Vanity Fair article about Microsoft’s lost decade. Countless users have come to appreciate Firefox, and recent gross revisions to it make me hope that Mozilla is not self-destructing.

    Comments by Nils (iirc) at Downthemall! seem to explain a lot. That was a really-popular extension. (Not techsically an add-on, iinm.) He said (and gave specifics) that rewriting his code would take far more time and effort than he could manage. Perhaps like many others, his is a very small group, iirc three people.

    I get the distinct impression, but of course could be quite wrosg, that Mozilla is doing wholesale censorship by disabling a very popular extension. Disabling it is part of what has disabled (apparently) just about every established add-on and extension.

    Another angle is that earlier versions of Ffx for Android are horror shows regarding security (apologies if I exaggerate), and tightening up security has become mandatory. Doing so “breaks” just about all established enhancements. I read that Android has become a popular target. Perhaps saying less is good strategy?

    I’m really surprised that so few people have posted comments here, and send Karen my condolences. Gave my nickname, this time.

  10. ‘Nicabod’ wrote on

    Not giving up yet, tried searching with the phrase
    earlier Firefox extensions disabled
    and found a bunch of helpful hits as well as history.
    A hit at Mozillazine was helpful, even mentioning Ffx 23.
    As to “helpful”, I mean that it gave explanations, but not anything likely to enable older plug-ins, extensions, or add-ons.
    Java and Javascript (quite different from each other)
    seem to have been the source of many problems.

  11. Grant Gayed wrote on

    I think the disappearance of nsIJSContextStack in Gecko 23 may be the cause of JS evaluations no longer working in our embedding case. I posted a question about it to!topic/ but haven’t heard anything back. Do you have any ideas, or could you point someone who would know at the question? Thanks!

    1. Jorge Villalobos wrote on

      I recommend that you post your question in a list with higher activity, like dev.platform or one of the JS lists.

  12. wildbill562 wrote on will not load in firefox 23, but it loads fine in Google Chrome. Please fix this…

  13. nina amr wrote on

    ican’t put add on iwant to my firefox in android like pocket emotions evry thing to computer only when idownload adds on telling me not compatible with your version iwant firefox for android like firefox for computer because ilove firefox and really found most feature iwant please do any thing to maked like computer thank’s for your work to maked like that