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?

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

  1. OMG

    Ok, since Firefox 57 I will only use Palemoon!

    I don’t want another multiprocess browser like Chromium clones.

    Well-loved. Like or Dislike: Thumb up 8 Thumb down 0

  2. Jim

    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.

    Like or Dislike: Thumb up 2 Thumb down 0

  3. Phil

    :( :(

    Like or Dislike: Thumb up 0 Thumb down 0

  4. Brennan Torres

    So this means Firefox will use Chrome’s Blink engine and become a Chrome clone which is possible right?

    Like or Dislike: Thumb up 0 Thumb down 0

    1. Sergey Tkachenko Post author

      No, they are not going to use Blink.

      Like or Dislike: Thumb up 0 Thumb down 0

  5. George

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

    Like or Dislike: Thumb up 3 Thumb down 0

  6. Marcos Jacoby


    “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)!

    Like or Dislike: Thumb up 1 Thumb down 0

  7. MDJ

    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.

    Like or Dislike: Thumb up 1 Thumb down 0

  8. SanyaIV

    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?

    Like or Dislike: Thumb up 0 Thumb down 0

  9. Bob

    Already uninstalled it and replace it with Pale Moon. Pale Moon is like the old Firefox before it became crap.

    Well-loved. Like or Dislike: Thumb up 4 Thumb down 0

  10. David Johnson

    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.

    Like or Dislike: Thumb up 1 Thumb down 3

  11. pd

    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.

    Like or Dislike: Thumb up 0 Thumb down 0

  12. Sargon

    Lol powerful extensions is the only reason I use Firefox. If they switch I might as well go Opera for the free VPN.

    Like or Dislike: Thumb up 0 Thumb down 0

  13. Schmarotzki

    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!

    Like or Dislike: Thumb up 0 Thumb down 0


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