If you’ve become dependent on a few Firefox extensions, going without them can be painful. You have two options to try and make those extensions work if you went with the Firefox upgrade but your extensions haven’t yet. These are more work-arounds than solutions and won’t fix the problem if there’s something architecturally different that prevents the extension from behaving properly. Sometimes it’s worth a try though.
Option 1:
Inside of each Firefox and Thunderbird extension (.xpi) is two particular settings. One is minVersion and the other is, you guessed it, maxVersion. These simply state which versions of Firefox and Thunderbird their developers recommend will work with this extension. It doesn’t mean it’s been tested with those versions specifically; it’s just a recommendation. If you’d like to test out the extension and see if it still works for Firefox even though the extension developers haven’t signed off on it, you can edit the files to make Firefox load it. This isn’t the best option as you create a branch from the original developer’s work and you might miss out on new features that they would implement with new versions. I’d recommend using this only as a spare tire to get you by until the developer releases and updated version that works with a newer Firefox.
You can download the .xpi file to get access to the files. Rename the FileName.xpi to FileName.zip and then open the .zip file and extract the contents using any extracting program: Windows Explorer, WinZip, WinRAR, 7-zip, etc.
The Extension Developer’s extension can be used to easily edit the Install.rdf to increase the version limit.
You can also use McCoy to sign your Install.rdf and Update.rdf to resolve the “does not provide secure updates” error message.
Once you’re done, just copy these files back into the .zip file replacing the originals. Then rename the FileName.zip to FileName.xpi. Then do a File, Open… to install the extension in Firefox.
Option 2:
Option 2 is a better alternative for end-users who just want a quick remedy to their Firefox extension woes. It, again, doesn’t guarantee that the extension will work, but it bypasses two checks that Firefox runs before enabling an extension.
Open a new tab and type ‘about:config’ in the address bar and hit enter. Click the ‘I’ll be careful, I promise!’ and proceed.
Right click in a blank area of the about:config page and go to New -> Boolean.
Enter the text for the preference name: ‘extensions.checkCompatibility’ and hit OK.
Next, set the value to False.
Add another boolean value as you just did for ‘extensions.checkUpdateSecurity’ and also set it to False.
Once you have these two settings, restart Firefox and your extensions will at least get past the Firefox checks to let these extensions run. You can test for yourself to see if they work. If they don’t and you have problems with them that crash Firefox, start Firefox in Safe Mode (shortcut in the Start Menu or right-click the special shortcut on the desktop) and toggle these settings to True in the about:config page.
With these settings enabled, you want to be wary regarding any extensions you install. You just opened a small window for malicious add-ons to get in by disabling Firefox’s own checks.