Mozilla to kill all existing extensions in Firefox 57

Mozilla today published the extension roadmap for Firefox, which reveals a huge shift with extensions in the browser. With the release of Firefox 57, support for all classic XUL extensions will be discontinued.


Firefox 57 is expected to be released in November 2017. The release will feature the switch to WebExtensions instead of XUL add-ons. Additionally, the special compatibility layer which exists currently for add-ons having issues with the multiprocess (e10s) mode will also be removed from the browser.

Firefox 53, which should be released on April 18, 2017 will have the multiprocess mode enabled by default for all users. If an installed add-on has the flag multiprocessCompatible=false, Firefox will continue running in the single process mode. The browser has a special blacklist of add-ons which have issues with multiprocess mode. If an addon is in the list and does not have the mentioned flag set, it will be disabled.

In Firefox 53, add-ons will only be able to load binaries using the Native Messaging API.

Finally, starting with Firefox 53, it won't be possible to submit any new classic add-ons to the (AMO) repository.

Firefox 54 to Firefox 56 will have multiple content processes and sandboxing. This is different from the single content process currently being used.

Starting with Firefox 57, the browser will only run WebExtensions. By that time, AMO will still host classic extensions and allow their authors to update them, but this won't be for long. The exact cut-off time for their support hasn't been determined yet. (via Mozilla).

Developers have less than a year to port their add-ons to WebExtensions APIs. The unacceptable thing about this transition is that WebExtensions are limited and not as powerful as the XUL framework.

Some users have an opinion that Mozilla is digging the grave for Firefox by discontinuing support for all the great extensions which made it such a popular browser. Once XUL support is killed, the browser won't be much different from Google Chrome except for the rendering engine. The rendering engine of Firefox is slower that Google Chrome's Blink engine. So, these radical moves can really change the market share for Firefox. Many users have already decided to switch to Vivaldi, Google Chrome or Opera.

What about you? Is this change in Mozilla Firefox acceptable to you?

Support us

Winaero greatly relies on your support. You can help the site keep bringing you interesting and useful content and software by using these options:

If you like this article, please share it using the buttons below. It won't take a lot from you, but it will help us grow. Thanks for your support!


Author: Sergey Tkachenko

Sergey Tkachenko is a software developer who started Winaero back in 2011. On this blog, Sergey is writing about everything connected to Microsoft, Windows and popular software. Follow him on Telegram, Twitter, and YouTube.

30 thoughts on “Mozilla to kill all existing extensions in Firefox 57”

  1. My primary browser is Pale Moon, but Vivaldi is already set up, with the extensions duplicated as well as possible. Opera testing is ongoing, as well as Chrome. Regardless of what occurs, one should be prepared for anything. Firefox is an afterthought at this point in time, as is IE. Let’s watch Edge develop.

  2. Final nail in the coffin. The once-beloved Firefox, officially turned into a Chrome clone. Happily using Pale Moon here, too.

  3. From

    “The future of Pale Moon is to maintain this general level of compatibility with traditional (XUL) Firefox-targeted extensions, although the (transitional) dual-ID setup will eventually be removed, at which point only Pale Moon targeted extensions will be accepted. This will still allow developers to target both Pale Moon and Firefox with specific code for them in a single package, but Firefox-only extensions will not longer be accepted by the browser when this lands.”
    “Unlike Firefox, Pale Moon will continue to offer full support for XUL and XPCOM binary-component extensions and there is no plan to discard the current extension system in lieu of Chrome-like alternatives (WebExtensions).
    Mozilla has already marked XUL extensions and bootstrapped extensions as “legacy” and will be phasing out support for all but WebExtensions, which will affect many Firefox extensions. We have no plans to do this and many “legacy” Firefox extensions will continue to be possible on Pale Moon when targeting it.
    JetPack (Add-on SDK) extensions”
    “With Pale Moon v27, no extensions of this type are supported anymore.
    As an alternative, a slightly-limited subset of the Jetpack SDK is available in the new PMkit set of libraries, included and available in v27.1 and beyond, which will offer support for many jpm-based SDK extensions. Extension developers can easily target this set of libraries with a few simple changes and a build specifically for the Pale Moon browser instead of Firefox.”

    Summarizing the whole text.
    If on the one hand they intend to maintain the use of add-ons via XUL but in the near future only if there is identification for use in PaleMoon which will exclude add-ons made only for Firefox on the other hand they abandon the JetPack support.
    The Adguard Adbloker extension for example no longer works on PaleMoon.
    To paraphrase an old popular saying with the characteristic brazilian humor, “it’s a double-legged knife” (double-edged knife in the original)!

  4. If they’re going to become just another Chrome clone then I’d rather switch to Chrome itself, Opera because of its dedicated developers or some other, less known browser. Single process for tabs (on my older PC this was more RAM friendly than multi-process behaviour) and variety of powerful add-ons were one of the main reasons why I chose Firefox in the first place. The last reason that would have made me stay was loading only main tabs at browser startup but if I recall correctly Opera already offers similar behaviour whilst Chrome has The Great Suspender extension. Oh, and not to forget that Firefox isn’t even optimized fo 64-bit operating systems.

  5. I’m using Vivaldi on my desktop and laptop computers but I’m using FireFox on my phone since it’s pretty much the only mobile browser that supports extensions. How is this going to affect extension support on mobile phones?

  6. I gave up on Firefox, and all its clones years ago. I got tired of extensions not working, perpetual crashing, and unintuitive operation. Chrome is just much easier, faster, and better.

    1. I still use Firefox for the time being but I stopped updating it when it started to become Chrome (aka Australis)… If I wanted to use a Chrome-like browser I would use Chrome, period. Same for Opera, I had used it in Android for years but stopped updating it when it started to behave like and use Chrome’s engine….

      Rest in pieces Firefox…. you were good when you were yourself, not a something’s else clone…

  7. The idiots in control at Mozilla need to stop reading How To Destroy Your Product For Dummies. The board should be sacked immediately. They’re a disaster.

  8. My primary browser is still Firefox 51, but I am also using Palemoon, Cyberfox, Opera 12.18, Firefox 38.8.0 ESR portable and Slimjet 13_x64 portable.If it’s not possible using my favorite addons in Firefox anymore I will change my primary browser or use an older version of Firefox.
    Sad but true, Firefox ist getting worse in every new version since version 38!

    1. “Sad but true, Firefox ist getting worse in every new version since version 38!”

      Yep, that was where I stopped updating it. I’m sticking with v38 (or whatever version was pre-Australis) as I didn’t like the Chrome-like UI and I don’t want to rely upon extensions (that ironically can become broken soon) to get back that classic UI.

  9. Without that extensions I’ve no reason to use Firefox. Already using Pale Moon and Vivaldi. Hope I can replace Firefox with it.

  10. If the extensions I use on a daily basis are ported to WebExts, then I’ll test FF, but if they don’t work, or not as I require, then I’ll look at Pale Moon, Vivaldi or Opera in that order.

  11. Yes but for how long will ALL and EVERy version of ALL the extensions Complete be available at mozilla firefox site. And if they decide to get rid if they are available elsewhere need to be cetificate to ensure no corruption continue to be secure place to get the add-ons.


  12. LOL SING …=… SIGN-UP :)

    no shouting just making it obvious for all we need fre easy access no hopps to jump through. Be like it is now at mozilla firefox or moreover be exactly the same, an exact mirror would do so it stays the same as it is now. Wayback etc are to unreliable to be trusted for this, long term forever servers needed.

  13. If you’ve got the time and space….

    Knock yourself out and mirror all the extensions yourself.

  14. Heck mirror all the extensions, themes, and collections while you’re at it.

    Strip out everything but a list linking to each file (stored locally or via hosting service) and post the url for everyone.

    I’m betting I wouldn’t be the only one smiling :)

    Mod : Feel free to merge my two posts as I did not see a way to edit my initial one.

  15. This is such bullshit… If I want to use Chrome I’ll download Chrome.. I don’t see how opening FF up to be able to use Chrome add-ons will help anything.. FF already has better add-ons that does shit Chrome cannot simply do with it’s restricted API access. I’m downloading every FF add-on today so when a better fork is created I have them. I don’t really like the current forks too much, but I think a huge fork will happen once FF [censored] its users.

  16. One update and they destroyed my years old browser. All major addons stopped working. Now I see advertisements big advertisement boards everywhere! Seems like a naked person anyone can sneak into.

    You FF motherf[censored], I regret, donating every single penny to you.

    They sure are going to die unless they revert back to v56 and shoot all board members in head and ass.

    I’m switching to Pale Moon and use Opera as secondary browser. As I switch, I wish them a horrible death.

  17. i liked (past tense) firefox. but recently, its has become more and more slow and bugy and the destruction of the addon collection made me decide to switch to chrome and whipe mozilla from my hard drive completely.

    soo long mozilla, for the time you where good, i enjoyed you. now youve become crap.

  18. What version is FF (not ‘fx’) THIS week LOL. So called “rapid release” — it is not the way to do software. It is the opposite of THINK first code later. FF, the world’s #2 political browser. Idiots.

  19. No, it is not acceptable to me…fortunately I foresaw this coming over 18 months ago, and began preparing. Last year I jettisoned Firefox from my XP Pro, and replaced it with Mypal, Centaury, Basilisk, and Slimjet. Last week I installed MX Linux on my secondary HDD, ditched Firefox, and replaced it with Waterfox, Ungoogled Chrome, TOR browser, and Slimjet. The only reason I had been keeping Firefox around was its add-ons. Mozilla Mothership finally found a way to effectively euthanize their browser. The dimwit fanboys will continue to slobber over Firefox irregardless of what it does or doesn’t do….dissidents like myself will kick it to the curb (with Chrome), and find other options.

Leave a Reply

Your email address will not be published.

Using Telegram? Subscribe to the blog channel!
Hello. Add your message here.