Making FireFox Add-ons Compatible With Your Version of FireFox

Posted by Yi Zhan

A quick guide to fix that problem.

So with Firefox 3 fairly recently coming out a lot of your old add-ons may not be compatible any more, well here is a quick guide to fix that problem.

First off find out which add-ons are not compatible go to Tools>Add-ons

A window opens telling you what add-ons you have installed. Look for the ones that are grayed out. if you click on a grayed out one it should
say 'Not compatible with Firefox 3.0.1' or what ever version of Firefox that you are using (at the time of writing this the most current version is 3.0.1.)

Now that we know which add-ons me need to update go to '' and search the add-on you have that is not compatible. Once you find the add-on click to go to the download page for that add-on.

The download button will be disabled saying that the add-ons is for an earlier version of Firefox, Use the 'User Agent Switcher' add-on to fake being the earlier version then right click the download link and click 'Save Link As...'.

Now we have the install file. Open it in any archiving app IE 7-zip, Winrar, etc. Open the file entitled 'install.rdf' in Notepad the file should look some what like this.

<?xml version="1.0" encoding="UTF-8"?>
<RDF xmlns=""
<Description about="urn:mozilla:install-manifest">
<em:name>SQL Inejct Me</em:name>
<em:creator>Security Compass</em:creator>
<em:description>An extension to test for SQL injection vulnerabilities</em:description>
<em:id>{ec8030f7-c20a-464f-9b0e-13a3a9e97384}</em:id> <!-- firefox -->

This is the part we are looking for:

<!-- firefox -->

Where it sayes '<em:maxVersion>2.0.0.*</em:maxVersion>' change that to '<em:maxVersion>3.0.*.*</em:maxVersion>' and save the file. A window will pop up in the archiving app saying File 'install.rdf' was modified.
Do you want to update it in the archive?

Click 'OK'.

Now exit out of the the archiving app and right click on your '.xpi' and click 'Open With...' and select Firefox from the list of applications. If all goes well Firefox will install the add-on with out a hitch.

Author: hellboundhackers