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Let Older Add-Ons Work With Firefox 3.0 164

mask.of.sanity informs us of a hack that allows old add-ons to work with Firefox 3.0. Short form: in about:config, create a new boolean and set extensions.checkCompatibility to false. "The fix, which requires a little boolean creativity, great for anyone not afraid of taking risks. The idea is to stop Firefox checking its version history, allowing defunct extensions to work... [Those who do] get the fix working will have to remove the code from the prefs.js file once the stable Firefox comes out, but will enjoy their [favorite extensions] in the meantime."
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Let Older Add-Ons Work With Firefox 3.0

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  • Do not do this (Score:5, Informative)

    by amake ( 673443 ) on Wednesday May 21, 2008 @03:10AM (#23489046) Homepage
    Not only is this not news, but it's a bad idea. Straight from the horse's mouth: []

    You can not make your extensions compatible by changing a Firefox preference.
    So don't do it unless you're fully prepared to deal with major breakage!
    • Re:Do not do this (Score:5, Informative)

      by DuncanE ( 35734 ) * on Wednesday May 21, 2008 @03:29AM (#23489168) Homepage
      While it may cause breakage its a great way for users of the beta and RC version of Firefox 3 to get some fairly major extensions work.

      I need IEtab to get certain work pages to work and I really love stumbleupon... So when Firefox 3 upgraded automatically to RC1 and these broke it was quite annoying so i disabled the check.

      An example of an extension this wont fix is Google Browser Sync. You will need to disable this in Firefox 3 otherwise you WILL see some major breakage if you disable the check.
      • Re: (Score:3, Interesting)

        by BZ ( 40346 )
        I would fully expect IETab to crash, in general, unless you're using it with the exact version of Gecko it was compiled against (or one completely binary-compatible with it, like the security releases are).
      • Re:Do not do this (Score:5, Informative)

        by GigaplexNZ ( 1233886 ) on Wednesday May 21, 2008 @05:26AM (#23489826)
        Odd, IE Tab is working fine here on FF 3 RC 1 without any modifications. That said, I find a safer way to get your favourite extensions working is to edit the version number in install.rdf which is inside the .xpi file (xpi is just a renamed zip file). That way when the extension updates normally, the hack doesn't stick around ready to break something later.
        • Re: (Score:3, Insightful)

          by DuncanE ( 35734 ) *
          Yes IEtab and stumble are compatible NOW, but werent for several days...

          If you know what you are doing then disable the compat check for a couple of days...

          And yes I know you can edit the extensions directly, but either they are going to get upgraded (like stumble) or they arnt (like Better Gmail2).
          • by pugugly ( 152978 )

            Yes IEtab and stumble are compatible NOW, but werent for several days...

            If you know what you are doing then disable the compat check for a couple of days...

            And yes I know you can edit the extensions directly, but either they are going to get upgraded (like stumble) or they arnt (like Better Gmail2).

            Interestingly enough I took you at your word, but Beta 5 *still* listed ietab as incompatible, no updates available when I updated.

            Works fine though, never killed it, never updated it further.

            Weird - Pug

      • Re:Do not do this (Score:5, Interesting)

        by ta bu shi da yu ( 687699 ) on Wednesday May 21, 2008 @06:41AM (#23490260) Homepage
        While it is fine to disable the compatibility checking, my concern is that if enough people disable it they might start expecting the Mozilla devs to actually implement workarounds to 2.0 compat problems in v3. That way leads to many, many problems. Just ask Microsoft.
      • Did you uncheck the "Warn me if this will disable any of my add-ons" box that is on by default? Because FF shouldn't have installed the update if it saw that your version of IEtab was incompatible with RC1 without asking you to ignore the incompatibilities. Might want to submit a bug report if that's the case.
    • Re:Do not do this (Score:5, Interesting)

      by Myen ( 734499 ) on Wednesday May 21, 2008 @04:07AM (#23489414)
      If I remember correctly, one of the top crashes for Firefox 3 betas was... people whole force-enabled Google Toolbar.

      Yes, top crash.

      This preference is generally not useful unless you know how to deal with the fallout (including figuring out what problems are due to extensions and which ones are not, and possibly fixing things locally).
    • Re:Do not do this (Score:4, Interesting)

      by __aabvlw4075 ( 670771 ) on Wednesday May 21, 2008 @04:11AM (#23489438)
      This isn't about making extensions compatible, it's about forcing Firefox to allow you to use extensions that claim not to be compatible, but very well might be. Major breakage certainly could occur, but I find it worth the risk. Many extensions that I was using with beta5 claimed not to work in rc1. Forcing them to load anyway has been very helpful, and they have all worked perfectly without causing any problems (as far as I can tell).
    • by Chrisq ( 894406 )
      Exactly. It is there as an aid to extension developers and testers. If you enable it and have problems with Firefox 3, don't blame FF3.
    • Not only is this not news, but it's a bad idea. Straight from the horse's mouth: []
      All the about:config preferences are detailed here: []
    • by Pahalial ( 580781 ) on Wednesday May 21, 2008 @07:42AM (#23490600)
      On that note, is there any -easy- way to check addon compatibility before upgrading to FF3, i.e. other than looking each addon up again? As I understand it they all have a builtin version range, why can't I just go to my addon list and see the compatibility of each addon?
      • Re: (Score:3, Interesting)

        by jalefkowit ( 101585 )
        Check the extension's listing on []. The site checks what version of FF you are using, so if you're browsing with FF3 and you look up an extension that hasn't been updated, it'll say "this add-on is for older versions of Firefox".
  • by BadAnalogyGuy ( 945258 ) <> on Wednesday May 21, 2008 @03:10AM (#23489048)
    If FF3 is being used before a v1 release, it ought to be used in order to find bugs so that the development team can fix them for the release version. By breaking a specific part of the product in order to install unsupported addons, users are adding unecessary unknowns to the equation and negating their contributions to the product test cycle.

    I'd say hold off on FF3 until it is released if you can't live without your plugins.
    • Re: (Score:3, Interesting)

      Personally, I've been using the betas of Firefox 3 as main because I couldn't stand Firefox 2. This RC1 release is heaven. You guys think this release is buggy when really there's just a few bugs to fix and most of them on foreign versions or very specific cases equally in windows, linux, and mac based on the ratio of installs.
      • Re: (Score:2, Insightful)

        by Anonymous Coward
        Pray tell, what's a foreign version?
        • I assume he means non-en-us language version.
        • A version that's been localized to a lesser used language that isn't the primary development language of the organization. As much as people enjoy telling the US and English speakers that they're not the center of the world, the point of the matter is the for these projects (and, also, this site), English is the primary language of the people who run it and the primary language of those who use it the most. This shouldn't mean that other languages are second class citizens or anything like that, but getting
    • by bloodninja ( 1291306 ) on Wednesday May 21, 2008 @04:28AM (#23489532)

      I'd say hold off on FF3 until it is released if you can't live without your plugins.
      While I planned on waiting until Firefox 3 is released before switching, I found it preinstalled in Ubuntu 8.04. So I'm using it. I do think that Ubuntu made a bad decision by including a beta web browser, I understand why they did that. The problem is not that the Firefox betas and RCs are buggy. The problem is that misuse of the term beta has led people to expect no less from a beta than from a full release. Gmail has been in beta for years, and it is [arguably] the most complete, feature-rich webmail available. How long was ethereal beta? 10 years? It was pretty stable for at least the past five years, at least, no less than any other full release software. Beta has become a marketing term for "new".
    • by Anonymous Coward on Wednesday May 21, 2008 @05:12AM (#23489758)
      In the same vein, shouldn't extension developers follow the Fx beta stages so that users will actually switch to 3.0 once it is released, instead of having to wait for months until their plugins have left beta stage?

      I use about 10 plugins since Fx 1.0, and have yet to encounter a single crash due to an extension (the only plugins that crash my browser are GCJ and Flash). Disabling compatibility checking has been a blessing for me, because it means I can use the latest version of Firefox and still use all extension that I don't want to browse without.

      (Before I knew of this option, I used to manually edit the extensions manifest file to fake compatibility with newer versions)
      • Someone mod this A/C up.

        He/she hits an important point that the parent missed. Pre-releases, while important for FF developer feedback, are also very important for FF add-on developer feedback as well.

        FF owes much of it's success to the powerful add-ons. I for one am not switching to FF3 on my main PC until all my add-ons are fully functional.
    • But if you find a bug you can simply start firefox in safe mode without extensions, or better yet a blank profile, to recreate the bug.
    • No way in Hell am I going back to the JavaScript performance - or lack thereof - in Firefox 2.
    • This doesn't really hold up, because for any bugreport, you're told to reproduce the bug in a clean minefield install (the nightly build) first. Since you're using another version without plugins to reproduce the bug anyway, it doesn't matter if the bug that the browser originally occurred in has weird settings. Besides, I don't really run the beta for the benefit of the product (although I will gladly report anything I see), I run it because it's better and faster, and I don't mind a slim chance of a crash
  • by Rah'Dick ( 976472 ) on Wednesday May 21, 2008 @03:12AM (#23489062)
    I always wondered why some extensions got disabled from one minor bugfix release to the next. Has the underlying API been changed so much, that the extension really isn't going to work anymore or is the extension's author just being a bit restrictive with the "max. version allowed" setting?
    • Re: (Score:3, Informative)

      by rubah ( 1197475 )
      Both. Things like forecast fox don't depend so much on the browser so long as they can sit happily in the statusbar (at least how I use it it's happy), but things like firebug get honest-to-gosh broken. As in you can open it and use it to edit css to show in a page, but it will not call the stylesheets or outline an element you hover over. So it's still kinda useful but heavily limited.

      for a given of 'small bugfix' anyways.
    • by WK2 ( 1072560 )
      Each extension has a "max-version". Some extensions devs will compare their extension with the current version of Firefox, say, make sure it works, and publish an extension with the max-version set to This is what they are "supposed to" do. When comes out, these extensions won't work any more, until the devs test them with the current version of Firefox, and upload a new version.

      Some devs "break the rules", and if the current version is, they will set the max-version of
    • by Patik ( 584959 )
      They're just playing it safe. Since each new release (beta or not) contains some changes, there's always a chance that one of those changes will negatively affect a particular extension. All the extension author needs to do is check that it's working and increment the version number. I realize this is inconvenient (especially when new releases come out every few weeks at this point in the cycle), but it's the only way to be sure that things work. If you don't care about being sure (as I don't), go ahead and
  • by Zouden ( 232738 ) on Wednesday May 21, 2008 @03:21AM (#23489116)
    What is this, the 'tips n tricks' column of a newspaper's IT section?

    The fix, which requires a little boolean creativity, great for anyone not afraid of taking risks.

    Not afraid of taking risks? It's about:config, not instructions for making a Linux-powered flamethrower, which I think would be a much better article for Slashdot.
  • It's a loss if old plugins don't work, some plugins are nice but unmaintained. An example was PrefBar which also suddenly didn't work anymore in FireFox 2.0, until much later. It's a shame that no backwards compatibility is provided out of the box. Not saying I'm for the above idea though.
    • There is already a browser for backwards compatibility. It didn't work out that well, that is why we have Firefox.
  • os dependency (Score:2, Insightful)

    by genican1 ( 1150855 )
    I hope that soon they'll disable the creation of OS dependent add-ons. Man, I really want my browser to match aqua. so what if I don't have osx?
    • Well, if that addon requires something that is only availiable on OSX then banning OS-dependant addons will either mean:
      a. those addons will break other installs or
      b. those addons will go away, denying the people who are capable of using it from doing so.
      Neither is particularily good.
  • by IBBoard ( 1128019 ) on Wednesday May 21, 2008 @03:30AM (#23489180) Homepage
    Obviously tips like this take a long time to filter through to Slashdot, for some reason. I saw that tip when first using Firefox 3 betas, and according to the Mozillazine knowledgebase [] it has been there since Firefox 2! It also covers an extra bit that the summary doesn't that might still stop extensions working in Firefox 3.

    And after all that, I originally used the Nightly Tester Tools to check the compatibility of some extensions. Some of the simpler ones worked, but AdBlock Plus couldn't just have the FF2 version enabled (it wouldn't auto-fill the filter address, but they have an update) and neither could the Web Dev toolbar (the edit CSS tab wouldn't close, amongst other things). Both of them have now been updated for the RC.

    I think this one is definitely tagged right - "!news". Now all it needs is "badidea".
    • by Cyvros ( 962269 )
      Another way apart from Nightly Tester Tools is to just download and open up the extension XPI (or theme JAR) in an archive manager, open install.rdf and then, under <!-- Firefox -->, change the <em:maxVersion>number</em:maxVersion> to 3.0.* - it'll see you through the rest of Firefox 3.
      • I've done that for themes, but the Nightly Tester Tools were more official and a bit less work (rather than trying to track down extensions by GUID). All of my extensions seem to have been made compatible by the developer now, though :)
    • And before adding the "version check" bool, they stored version numbers in the preferences. There were separate values for application version and extension version, allowing you to specify the previous version to extensions so that they could work without having to wait for the author to update the addon.
  • See here []. I've been using it with no problems for B4,B5 and RC1. The only problem I have here with RC1 is with AVG 8's safesearch.

    Right now the only thing that (was, is?) giving me grief on RC1 is the blasted urlclassifier bug which thrashes the hell out of the hard disk (but that seems to be better now I've had RC1 a few days).


  • Nightly Tester Tools (Score:5, Informative)

    by DemonThing ( 745994 ) <demonthing@[ ] ['gma' in gap]> on Wednesday May 21, 2008 @03:33AM (#23489214)

    This addon [] lets you selectively override addons' compatibility, among other things.

    This extension adds a few extras useful to those that regularly test nightly builds of Firefox, Thunderbird, Sunbird and Toolkit Seamonkey (Suiterunner).

    The following is a brief list of the extension's features, for the full set of features please visit the extension home page.

    • Extension compatibility fixing
    • Titlebar customisation
    • Build ID retrieval
    • Screenshots
    • Breakpad information
    • Restoring tabs from previous session
    • Leak log analysis
    • This addon [] lets you selectively override addons' compatibility, among other things.

      I do use NTT, but I don't like it for addon compatibility. When you use NTT, it edits the version number listed in the addon. It spoofs the author stating that the extension is compatible. Its compatibility setting is simply changed to state that it supports the current version.

      When you use the extensions.checkCompatibility option, it simply overrides the function that automatically disables old extensions. Setting the option adds a warning banner to the top of the Addons window stating that checking is

  • Latest version of Foxmarks doesn't work :( Oh well, it was worth a try!
  • Every extention has an install.rdf file which contains the version numbers it works with, if you go to your profie dir and then extentions you can move the extention folders out, edit the rdf files in notepad then restart firefox - it will have no extentions, close it, then move all the extention folders back one at a time restarting firefox everytime, that way you are only adding back extentions that you know work, but just haven't been updated by their developers to install. This can also be done by renam
  • by Idaho ( 12907 ) on Wednesday May 21, 2008 @04:12AM (#23489444)
    Sure you can disable the mechanism that checks whether plugins are compatible.

    However, as is to be expected with major version changes, lots of API's will likely have changed, so if the plugins happen not to crash outright, they might fail in subtle ways that you don't discover until it's much too late.

    This is pretty much exactly why the mechanism is there in the first place.

    So if you do this, don't complain about "bugs" regarding crashes, memory leaks and pretty much any other problems you may experience with Firefox. There likely will be a lot, if you go down this road.
    • Re: (Score:2, Insightful)

      by Waccoon ( 1186667 )

      Not to sound terribly dumb or inexperienced, but should we really expect extensions to cause crashes, memory leaks, and pretty much any other problem we might experience with Firefox?

      Don't extensions run on some kind of VM or something? People yell at Windows for all of its stability problems, and practically everything in a modern web browser behaves like it's single-threaded?

      We do live in 2008, right?

      • Re: (Score:3, Interesting)

        by Tim C ( 15259 )
        practically everything in a modern web browser behaves like it's single-threaded?

        Yes it does, hence the entire browser stalls when one tab is busy for some reason.
        • Do you know if that has ever been acknowledged by the dev team? My google skills are failing me right now...but that is pretty much my last complaint with this browser.
      • by Idaho ( 12907 ) on Wednesday May 21, 2008 @08:15AM (#23490822)

        Don't extensions run on some kind of VM or something? People yell at Windows for all of its stability problems, and practically everything in a modern web browser behaves like it's single-threaded?

        I agree about the singlethreaded thing. Apart from that: no, extensions can't run in some kind of VM. If they did, they would not be able to modify the browser in interesting ways (as this in many cases needs r/w access to internal browser state; this would not be available if you run it in a "sandbox" or VM.

        You can pretty much have the exact same argument about Linux kernel modules: the kernel refuses to load modules that are compiled for the wrong (=a different) kernel version. Now, you could say, modules should not be able to crash the kernel, right? Well...if you could limit the interface between kernel and modules in such a way that modules would probably run about 5x slower, needs twice the amount of code to write *and* be unable to do a lot of things that would be interesting because the strict interface does not allow this, then yes. If we don't want to make that sacrifice (and in fact we don't), the smarter way is to only allow modules to be loaded that are actually at least compiled against the correct kernel version.

        We do live in 2008, right?

        Last time I checked, yes. Your point being that software composition problems are just supposed to somehow magically solve themselves these days?
  • Can someone please explain to me why you people are posting saying "don't do this".

    The entire essence of slashdot is to fuck around with technology. Saying "you shouldn't tinker" is the opposite of what we are about.

    I say go for it! Rip apart the browser and mess with it to your hearts content - cause that's the only way you'll ever figure stuff out.

    The following plugins are working for me now,
    Adblock Plus
    Firebug 1.1.0b12
    Google Pagerank Status 0.9.8
    StatusbarEX 0.2.11
    Web Developer 1.1.6
  • by hyperz69 ( 1226464 ) on Wednesday May 21, 2008 @04:34AM (#23489566)
    Here is another boolean hack but for Vista! Just set that boolean variable


    to FALSE

  • While the plugin system has many advantages, it becomes a management job in itself. Without plügins Firefox is well... daft. With plugins they stop working on certain upgrades, people claim plugins are the cause of instability and memory losses and so on. I don't want or need to micromanage my browser. I'd like Firefox and some of the core plugins as one package released together, but I guess that's why I prefer Opera. It's one install every time, it's not nearly as flexible as Firefox but it's a lot l
  • by MadMidnightBomber ( 894759 ) on Wednesday May 21, 2008 @06:58AM (#23490356)
    You have been warned :)

    Recovery is to delete the plugin, something like this:
    egrep -ri google .mozilla | grep toolbar
    .. ( see where it lives ) ..
    rm -rf .mozilla/firefox/zy8uo2wh.default/extensions/\{3112ca9c-de6d-4884-a869-9855de68056c\}

    • Re: (Score:2, Informative)

      by mstrom ( 1060158 )

      Recovery is to delete the plugin, something like this:


      Ouch,manual removal of add-ons :(

      Simpler way is to start Firefox in safe mode which has an option to disable all addons on startup, after which it can be uninstalled from within firefox safely.

      firefox -safe-mode if my memory serves

  • by egghat ( 73643 ) on Wednesday May 21, 2008 @07:42AM (#23490598) Homepage
    I'm on OS X and FF3 doesn't allow a parallel installation of two Firefoxes.

    Is there a way to test all my installed extension in advance?

    Sorry if this is a dumb question but I couldn't find anything with googling.
    • by CXI ( 46706 )
      Is there a way to test all my installed extension in advance?

      VirtualBox. Just spin up a VM of your favorite (supported) distro and test away. You could even run in seamless mode for a while if you're inclined to think "blah, then I'd have to use the VM for a while which would mean switching windows constantly etc, etc".
    • by stubear ( 130454 )
      OS X does allow for parallel installations of Firefox, you just need to rename at least one of them, I add the version number behind both, and you're good to go. I have Firefox 1.5, 2.0 and 3.0 all running on my Tiger Mac at work and Firefox 2.0 and 3.0 on my Leopard Mac at home. You can't run both simultaneously (not sure why) and Firefox will check for compatible updates to add-ons after starting a different version (for instance, start 3.0, close it then start 2.0 and Firefox will insist on looking for
  • by lofoforabr ( 751004 ) on Wednesday May 21, 2008 @08:32AM (#23490956) Homepage

    Well, I've been using this pref since the early days of Minefield. I find that most extensions I use work fine under Minefield. Here is a list of them:

    • Adblock Plus
    • Fasterfox
    • Flashblock
    • Greasemonkey
    • Live PageRank
    • NoScript
    • Web Developer Toolbar

    One thing to note, though.. I think recently the mozilla addons site has been changed, and the button to install is now disabled if you use a not-officially-compatible browser version.

    To overcome this, I first install NoScript (it's compatible with Minefield), and then blacklist the mozilla addons site, so it will not run the javascript that disables the button (yes, it's javascript). Then I can install whatever I want.

    Of course, I had a few problems with some extensions. Turned out they really were incompatible, but from my personal experience, most of them work just fine under Minefield.

    • There's an easy way to get around that. Click on the 'Older Versions' link, then just save to the desktop. I do it by highlighting the hard link to the extension and wget'ing it.

      Then, to install it, just open up the Tools>AddOns box and drag the extension into it.
  • > [Those who do] get the fix working will have
    > to remove the code from the prefs.js file once
    > the stable Firefox comes out

    Not true. There is highly visible UI in the Firefox 3 AddOns Window which lets you to turn compatability checking on again.

  • This is a weak idea for a story, the same advice is commented on somewhere with every new Slashdot post about Firefox releases.

    Better advice would be to go check the Addon's web site and see if there's a beta version that been tested with the new Firefox release. Many of these extensions are written for free and have donate buttons on the site. If you donate to the author, he may be more inclined to "fix" your favourite extension to ensure compatibility.

    Far better than making your browser unstable!
  • Dumb dumb dumb. Most of the popular extensions have beta and dev releases that are compatible with ff3. IMHO, it is better to monkey around with the dev release and maybe get bugs fixed than just live with a mostly broken "compatible"ized extension hoping that it will be updated by the time the official release comes out. THIS IS WHAT BETA (and RC's now, I guess) IS FOR!
  • Most uncomplicated extensions will work fine with the new Firefox. The reason that all will fail by default is that ALL extensions must have a string stating which versions of Firefox they are compatible with -- so when a new version of Firefox comes out, the developer must test their extension, and modify the compatibility number.

    For most extensions, it's as simple as changing 2.0.+ to 3.0.+ or something similar and it will work fine.

    BUT there may be minor code changes that require a partial rewrite of

  • I could have submitted this story any time in the last few years (ever since I found out about the setting in 1.5 or 2.0 betas) and gotten on the front page of Slashdot. And I thought it was common knowledge!
  • Firefox Portable (Score:3, Informative)

    by EnOne ( 786812 ) on Wednesday May 21, 2008 @11:40AM (#23493336)
    I would recommend Firefox Portable if you want to see if FF3rc1 is right for you. No registry changes and it allows you to add your extensions without issue. I have 10 add-ons that I use with Firefox and last time I tried to do a blind upgrade with forced add on use Firefox would not even start.
  • Location Bar (Score:3, Interesting)

    by Toonol ( 1057698 ) on Wednesday May 21, 2008 @01:53PM (#23495154)
    I just installed Firefox 3.0 this week. I'm generally happy with it, but is there a fix for the horrible location bar auto-complete yet? My jaw dropped when I saw it pop up... what an ugly, ugly, feature. It seems like a pet change of the creators, too, so they don't have any option to turn it off in about:config.

Experience varies directly with equipment ruined.