Make older add-ons work with Firefox 3.0:
By Neil McAllister
May 20, 2008 (PC World) If you’re like me, you’ve been playing around with the beta releases of Firefox 3.0. The new version of the open-source browser is better-looking, uses less memory, and feels snappier all around. There’s just one problem: Every time a new beta version comes out, some of your extensions and add-ons are bound to stop working. With Firefox 3.0rc1, almost none of them work.
Fortunately, there is a solution that will “fix” all of your extensions at once. But I caution you, it’s not for the weak-hearted. The fix doesn’t take longer than a few seconds, but when it comes to troubleshooting your browser afterward, you’ll be on your own.
I can’t repeat this enough. DO NOT TRY THIS unless you are comfortable editing the advanced preferences of your browser. And don’t do anything until you’ve read through this entire post. Don’t say I didn’t warn you.
In my experience, extensions that worked with Firefox 3.0b5 will generally be stable with 3.0rc1. It is possible, however, that some of them will cause the new version of the browser to crash. It might even crash on start-up — which means, obviously, that you won’t easily be able to undo the fix I’m about to describe.
The key to the fix is to prevent Firefox from checking its version number before it tries to load extensions. To do this, you will need to set a new preference value. Point your browser at the URL “about:config”, then right-click on the preferences list to bring up the contextual menu. You should see an option that says “New.” Select that, and choose “Boolean.” When it asks you for the preference name, type “extensions.checkCompatibility” (without the quotes). You have to enter the name exactly. For the value, choose “false.”
Update: seems it didn’t work for my specific plugins. 🙁