Install Firefox 3.6 add-ons in Firefox 4 beta, disable compatibility check
Posted on June 30, 2010
Update (March 22, 2011): this post also applies to Firefox 4 final. Just use extensions.checkCompatibility.4.0 instead of extensions.checkCompatibility.4.0b.
Firefox 4 beta is available. I installed the 64bit version on Linux today, it’s notably faster than previous versions and includes several other improvements such as tabs on top. Now, I don’t want to go back to 3.6.
As usual the only thing holding me back from upgrading is add-on compatibility. Luckily it’s possible to disable the compatibility check so Firefox 4 will let you install add-ons built for older versions, I found that many add-ons work just fine in Firefox 4.
Disable compatibility check
If you’re willing to take your chances, navigate to about:config in your browser, promise not to break anything and right to window click to add a new boolean. In the preference name field, add extensions.checkCompatibility.4.0b and set the value to false. Firefox will now let you install any add-on.
If anything breaks, try disabling add-ons or delete them completely. You can always go back to 3.6 if nothing works, and wait for a new stable release.
I’ve tested it with AdBlock Plus, Firebug, Flashblock and Wappalyzer.
I'm ElbertF, a Dutch expatriate web application developer in Melbourne, Australia. I use and create open-source software.
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Comments (5)
thanks man
Posted by :) on October 13, 2010
Hey there!
I’ll give it a try.
Btw: I just entered the deepweb.. This is my first post in here.
Posted by :] on December 02, 2010
That seemed to work for every add-on except FireFTP. It comes up, but has no connect button or add new.
Posted by Wayne on January 28, 2011
Oops! It broke my Firefox 4beta11 installation!
I think the culprit was Tab Mix Plus (0.3.8.4) (at least partly) I couldn’t get to the Tab Mix Plus options… an error message appears in a big box with a few (4 lines?) lines of code. (sorry wasn’t able to get a screencap of that). I couldn’t access any website, can’t get to about:config… etc. In short, it was rendered useless.
ABOVE: my Firefox after the tweak.
_________________
ABOVE: a few of my addons.
Posted by Lorgen Shadouness on February 25, 2011
Be sure to disable Tab Mix Plus with Firefox 4 until it’s compatible [Why? See my earlier comment/post]. I was able to disable it… (after some backups, uninstallation, reinstallation, copying… et al.) and things are going well again! =’)
[Memory use though, is probably as high again :’/]
(However, now that I can use Firefox 4 here (with the addons enabled) I can’t drag and drop images here for posting :’o)
Posted by Lorgen Shadouness on February 25, 2011