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October 20th, 2008
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extension
firefox
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Getting your extensions to work in the Firefox 3.1 Beta
If you’ve been running the Firefox 3.1 beta for the last few days like I have, you’re probably beginning to miss all those fun extensions you took for granted in 3.0. Sure, you could install nightly tool addons to disable version checking for you, but I feel dirty having a hack like that running all the time in the browser. Instead, I discovered a far more elegant solution: just edit the XPI.
First, grab 7zip. It’s a free archive manager like WinZIP or WinRAR, but it plays nice with the XPI format. Now, go to the Mozilla Addons site and find the extension you’re looking to install. The “Install” option will be disabled, but no worries, just scroll down and hit the “All Versions” link. Now you’ll have one or more versions listed with enabled Install buttons, but using those won’t work: they’re marked internally as working with Firefox versions up to 3.0.*. This is what we’ll need to change.
Right click the Install link for the most recent plugin version, and save the XPI file to your desktop. Now, load 7zip and open that XPI file in it. Find the “install.rdf” file, right click and pick Edit. There’s a lot of nonsense in these files, but all we’re worried about is one string:
em:maxVersion="3.0.*"
Once you locate this line, change it to read:
em:maxVersion="3.1.*"
Save the file, allow 7zip to update the archive, then close 7zip. Now, in Firefox, go to the Addons window from the Tool menu and switch to the extensions tab. Drag the XPI from your desktop into your addons list. Firefox will install the addon for you without complaint. Restart Firefox and you’re done!
This hack will work for most extensions as there has been very few changes to the core functionality of Firefox in 3.1; most of the changes are to the Gecko rendering and JavaScript engines. I’ve successfully installed all my essentials in 3.1 without any problems, but if you do end up running into an addon incompatibility issue you can always start Firefox in Safe Mode from the Mozilla Firefox group in the Start menu.
Hope this helps!