Mozilla outlines Firefox 25 compatibility changes

Alan Buckingham
May 28, 2013

With Firefox 21 having just been released as a final version, and new builds now running in beta, aurora and nightly, Mozilla is now looking ahead to what is next. Version 25 of the web browser is on the horizon, and the organization has already begun to look forward and talk about what customers can expect.

What exactly to expect, according to Mozilla, is better compatibility. "There are two major add-on compatibility changes to look forward to, and I’m giving you this heads up just so that you’re aware and plan ahead" says Mozilla's Jorge Villalobos.

The first change is a major theme revamp. Australis, which has been talked about for some time, is set to simplify the user interface and bring major changes to how toolbars work. Mozilla also tells us it is considering completely removing the add-on bar, though no final decision on this has yet been made. The main toolbar will also have a dedicated area for add-on buttons and widgets, and it looks possible that user-created custom toolbars will also be gone, the organization says.

Planned changes:

  • Add-on bar may still be removed.
  • User created toolbars will be removed
  • Main toolbar will have space for add-on buttons and widgets

Second, session-restore will also be overhauled. There are many add-ons that are reliant on private variables (beginning with __SS) that will no longer exist. For developers with add-ons that may be affected by this change, Mozilla has published a list and recommends that you check it.

Some of the popular extensions that are included on this are Twitter, Bing for Firefox, IE Tab, Tab Mix Plus, and more. If these are not updated, then they will all be gone in version 25 of the web browser.

Additional information about the second change are available on Bugzilla where it is listed.


Mozilla promises that as Firefox 25 approaches (release is scheduled for October) it will have more information and better documentation. At the moment, this is just a heads up on what is coming, but the news is exciting, except perhaps for developers who must change add-ons or have them rendered useless.


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  1. Abhijit said on June 1, 2013 at 9:31 am

    I hope they give us a choice of which look we want similar to the skin concept
    They can give us 3 choices
    2.Firefox 4.0+
    3.Firefox 3.0-4.0

    1. Orhin said on June 1, 2013 at 12:11 pm

      There will be no choice. What we get is Australis with many Customization Options removed.

      That is Mozilla’s Future wish, already existent in- Browser Customization limited to moving some add-on Buttons to the upper bars or removing them, and perhaps if we are lucky we can move the url element in the same bar from left to right, while the rest of Customization options is left for Add-On Developers to be inserted again.

      And we all know what happens if good Add-Ons get abandoned in the future….

  2. Dougle said on May 30, 2013 at 7:14 am
    1. Martin Brinkmann said on May 30, 2013 at 7:45 am

      Thanks. As far as I understand it, it removes the button that triggers the sidebar, not the sidebar itself. So, the only option is to use the view menu or the shortcuts once implemented.

  3. reality said on May 30, 2013 at 12:19 am

    Man behind Google spywares wants just extend present indirect control over most FF/Opera users (who dont tweak privacy), by changing functionality of browsers, on more advanced users .
    “simplification” means gradually curbing addons based freedom – aim is no Adblock-ing and NoScript functions in future .

  4. Dave said on May 29, 2013 at 9:42 am

    Why not just distribute Chrome? Removing toolbars is just plain STUPID. Gee, I’m scared ’cause this is making me want to look at IE, yuch.

    1. Compuitguy said on May 29, 2013 at 10:01 am

      the changes are no biggie for me

      but your last line “I’m scared ’cause this is making me want to look at IE, yuch.” made me LMAO

  5. Guest said on May 29, 2013 at 7:52 am

    And so begins the age of waning.

  6. Anonymous said on May 29, 2013 at 4:45 am

    Firefox has gone the way of Microshit Windoze 8. Don’t bother with software that takes away useful features and keeps you in an upgrade loop.

  7. Peter (NL) said on May 29, 2013 at 3:17 am

    Does Mozilla have an even so loyal user base as the Opera browser ?
    OMG, there are already 25 pages with comments on the Opera 15 preview desktop version …

    Maybe the Mozilla management team can take notice of that !!!!!!
    Red line: Do not screw up our browser !!

    1. Martin Brinkmann said on May 29, 2013 at 3:34 am

      Peter, one has to consider that the changes proposed for Opera are turning the browser upside down which should get more users pumped up. If Mozilla would announce a move to Blink or Webkit, it would probably receive a similar amount of flak or even more than that.

  8. Gennaro Prota said on May 29, 2013 at 2:43 am

    Hi Martin,

    why do you say “the news is exciting”? My personal opinion on this is that they are focusing on aesthetics (mainly), which has its own importance but is certainly a bit down on the list with respect, say, to how Firefox still corrupts its SQLite databases or its profiles in general. Firefox seems pretty feature-mature by now; IMHO the priority is to make it robust (in as far as possible, given the messy codebase and their development process).

    1. Martin Brinkmann said on May 29, 2013 at 2:46 am

      It is Adam’s article, not mine ;)

      1. Gennaro Prota said on May 29, 2013 at 3:06 am

        Aha, my bad for not checking :-) Now I see why your comment above wasn’t highlighted with a colored box.

      2. Martin Brinkmann said on May 29, 2013 at 3:34 am

        I’m usually not as easily excited as Adam is ;)

  9. SuilAmhain said on May 28, 2013 at 9:15 pm

    Agh!!! Change!!!

    The people who designed Firefox in the first place and are entitled to most of the kudos for the mostly still open web 2.0 world we live in are entitled to the benefit of the doubt. The beauty of Firefox is if you don’t like what Mozilla is doing, fork it and do it your better way.

    1. anon said on May 29, 2013 at 12:13 am

      Argh! People have opinion!

  10. Jim said on May 28, 2013 at 5:10 pm

    I’ll install it in a VM just to see what it looks like, but I doubt I’ll use it on a real system. Like several others here have stated, I’ll disable the updates. Maybe it’s time to give SeaMonkey a spin.

    1. Orhin said on May 28, 2013 at 5:19 pm

      I already have tested the preview on my netbook, Looks like Chrome, Smells like Chrome and Feels exactly like Chrome.

      Looked at it, hated it like Chrome and deinstalled it also as fast as Chrome.

      Who is loving how Firefox looks, feels and smells right now will hate Australis with Passion!

      Nothing more to add to that!

      1. Boris said on May 28, 2013 at 9:10 pm

        I bet you will be able to change to a different theme just as right now. Removing addonbar is a huge mistake.

  11. Orhin said on May 28, 2013 at 2:04 pm

    Fine for me, Mozilla should do what they want with their new Created “FireChrome” :D

    Since V24 will still be Australis Free, i declare Firefox Aurora 24 when it is coming as my last official Firefox Version which stays unchanged on my Machines, I update my Profile one last time for all Add-On Changes when V25 starts to hit Aurora Release Channel to grab all last updates, then switching off Update Function for Add-Ons, Themes and the Browser itself.

    And with some changes you can even make sure that Mozilla forces you not to “Force-Update” Firefox like they have done it once in the past.

    Aurora V24 will be enough for watching Websites for a long time to come in quite a compatible way :D

  12. Anon said on May 28, 2013 at 1:34 pm

    This is like a sick joke.
    I see the “Let’s ruin everything that may make Firefox desirable” plan is still going.

  13. Nebulus said on May 28, 2013 at 1:25 pm

    Firefox is becoming more of a Chrome clone, and Opera is going the Chrome way as well… Goodbye, choice! :(

  14. hum said on May 28, 2013 at 11:46 am

    So 24 ESR is going to be the most used Fx-version for a very long time.

    1. Martin Brinkmann said on May 28, 2013 at 12:59 pm

      True, probably as long as Opera 12.15.

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