How To Make Any Firefox Add-on Compatible with All Versions

Joel Reyes 11-03-2009

firefox addons compatibility Sometimes trying out newer versions of Firefox, especially ones that are still in beta, comes at a cost. Since the version you’re running is so new, add-on developers haven’t had the chance to update their add-ons to work with the newer versions.


So this is when you stumble upon an add-on that conveys the following message to you: “This add-on is for older versions of Firefox”.

firefox extensions compatibility

Fix Incompatible Add-ons

Since your sights are set on using Firefox extensions that keep telling you they’re incompatible with the version you have, and downgrading a version or two isn’t an option, now you can discover a nifty tool called Nightly Tester Tools.

firefox addons

Ironically this is a Firefox add-on that will help you make all other incompatible extensions compatible with the browser version you’re running.


What’s Next

The first step you need to take is to download Nightly Tester Tools here, if you haven’t already.

How To Make Any Firefox Add-on Compatible with All Versions firefox img 3

Next if you still have the extension that was disabled when you upgraded to a newer version of Firefox in your add-ons menu, then you will go to Tools/Add-ons and right-click on your disabled extension, then choose Override Compatibility.

How To Make Any Firefox Add-on Compatible with All Versions firefox img 4

Now it will ask you to confirm your selection by clicking Force Install.

How To Make Any Firefox Add-on Compatible with All Versions firefox img 5

The last step involves restarting Firefox to have your add-on fully working.

Bonus Features

Here you thought it was the end of this add-ons story but actually there are a few other features that this extension allows you to take full advantage of.

With Nightly Tester Tools you’re also able to take screenshots of any webpage and save them in JPEG format. You can easily restore tabs from a previous session if it just so happens that your PC froze and you didn’t have time to properly close your browser window.

How To Make Any Firefox Add-on Compatible with All Versions firefox img 6

Feel free to test all other Nightly Tester Tools features and let us know how you like them in a comment below!

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  1. Tech Man
    March 20, 2018 at 3:01 am

    I want to do the exact opposite; install a new addon (DuckDuckGo Privacy Essentials) on an old version of Firefox (52 ESR). And it MUST be the current version of the addon, at least 'requiring' FF56 or later.

  2. Anonymous
    January 19, 2016 at 9:17 pm

    Doesn't work as described. On FF 43.0.4, with this Nightly Tester Tools 3.7.1-signed, if I right click I only see the "Enable" menu choice if it is something I had manually disabled.

    If it was instead something that FF disabled itself when it did the compatibility check after updating itself to a new version #, then the disabled extension has red text that reads "[Extension name] could not be verified for use in Firefox and has been disabled.", and right clicking doesn't show the "Enabled" menu choice at all.

    Thus, this extension is essentially useless to me for the purpose described in the article. Yes I did restart Firefox before observing this. Even removing the Nightly Tester Tools extension, I still have the same choice to Enable things manually disabled and lack that choice for things FF itself disabled, so in summary, the Nightly Tester Tools simply does not any longer do what the article claims.

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    November 29, 2009 at 6:18 am

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  5. Chris Lozeau
    November 4, 2009 at 7:32 pm

    Ironic how I have to 'force install' Nightly Tester Tools to be compatible with Firefox 3.5

    • Tech Man
      March 20, 2018 at 3:02 am

      Can you tell me how to "force install"?

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    September 10, 2009 at 3:38 am

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  7. Codrin
    July 27, 2009 at 4:37 am

    My problem was resolved. After updating to 3.5 my life pagerank stooped working, but with this tool is now again at work. Thanks !

  8. adit
    July 15, 2009 at 11:08 pm

    i have problem,,,can help me to explain how to make add ons for mozila,,,,

  9. aiiee
    June 30, 2009 at 3:28 pm

    None of this works in 3.5.....

    Any ideas?

  10. شات صوتي
    March 29, 2009 at 6:37 pm

    My Firefox is hanging and crashing even I am using compatiable add-ons and updated version of Firefox ,does I really need to force an add-on to install and get probelma with Firefox

  11. Mackenzie
    March 13, 2009 at 9:40 pm

    The title is wrong.

    This does NOT make the extensions compatible. It makes Firefox ignore the fact that the extension isn't meant to be compatible with that version of Firefox. It might turn out that the extension is compatible and just needs to have its version string updated. It's just as likely that it'll turn out that you need to rewrite half the extension to make it compatible.

    It's like forcing Vista to try to install a program for Windows 95. Hey, it might work. It might also give you a blue screen of death.

    • Mark O'Neill
      March 14, 2009 at 7:21 am

      But the extensions are still compatible in that they work with that Firefox version. You're just arguing with semantics.

    • Joel Reyes
      March 18, 2009 at 2:51 pm

      Like Mark pointed out it, this add-on still makes your extensions compatible whether forced or not. You have to see it from this perspective, the add-on was NOT compatible before the tester tool, then once you utilized the tool even if it is a forced compatibility you're then able to use it.

  12. renevranc
    March 13, 2009 at 2:41 am

    nighty tester is not compatible withe firefox 3.0.7

  13. venkat
    March 13, 2009 at 1:46 am

    @Joel reyes
    I apologise for the comemnt I made above it's too harsh ,when using beta versions of Firefox there is no other way to use Firefox add-ons comaptable with Firefox is through nightly tester tools ,since there is no option available .

    • Joel Reyes
      March 18, 2009 at 2:48 pm

      No problems. We always appreciate any insight on our articles. Everyone's entitled to an opinion. :)

  14. Aaron Spuler
    March 12, 2009 at 11:35 am

    As an extension and theme author, I might shed a little more light on this subject....

    While the nightly tester tools and the about:config entry can allow a non-compatible extension to install, it is by no means a guarantee that the extension or theme will work as expected.

    The reason for this is because the theme and extension APIs change with each version of Firefox. Extensions and themes have a block of code in their installers that specifies what versions of Firefox they have been certified for by their author (minimum version and maximum version).

    If you do decide to use a theme or extension that is not yet certified for your version of Firefox and it does not work as expected, please remember that the author has not certified it for that version of Firefox. Take that into consideration when contacting the author to report the bug.
    I've had several users email me over the years, irate that an extension or theme did not work as expected on a version it had not yet been certified.

  15. Miguel Wickert
    March 12, 2009 at 11:09 am

    Okay, not to shabby- I'll play around with it... thanks for sharing. I'll try to get Firebug working with this nightly tester. Any thoughts?


  16. dentrite
    March 12, 2009 at 10:04 am

    It works well in my new firefox, but it seems that not all extensions works with it.

    I had Chromatabs installed in previous version, and i forced install it with Nightly Tester Tools, but no magic happened here when others did.

    you may want to know this.

  17. venkat
    March 12, 2009 at 7:08 am

    My Firefox is hanging and crashing even I am using compatiable add-ons and updated version of Firefox ,does I really need to force an add-on to install and get probelma with Firefox .

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    March 11, 2009 at 10:43 pm

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  19. Joel Reyes
    March 11, 2009 at 8:49 pm

    You could go about validating extensions that way as well, though there's a possibility that not all expired extensions will respond to the "extensions.checkCompatibility false" format.

    Though once you install this plugin you never have to install it or deal with it again. Both ways are simple, however its just a matter of which one is simpler for the individual to deal with. :)

    Thank you for your comment Charax!

  20. Charax
    March 11, 2009 at 7:21 pm

    What's wrong with just adding "extensions.checkCompatibility false" to about:config? I've been using this for months to get old extensions to work with the latest beta until a compatible version comes out and you don't have to install all the nightly tester tools to do it.

    the simplest way is usually the best - adding one boolean variable to about:config is better than installing a whole suite of functions just for the one you want.