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A brief introduction in opening xpi files and changing the plugins install file to work with newer versions of Firefox.
Firefox 4 and your older plugins.
So if you are like me and you update to the latest Firefox to find that your plugins are not supported, you feel a little bummed out.
Well, there is a way to truly test whether or not your plugins are functional. If you don't know already, Firefox plugins are .xpi file extensions
that are really just .zip files. You can just rename your file to a zip file extension to see the goodies inside.
Method 1: If your computer shows the extensions on files then just: Right click >> rename >> clear out .xpi and replace with .zip
Method 2: If not the previous method, then maybe this: Open a terminal (console) >> navigate to the directory of the xpi file and use the rename command
i.e. Windows: rename plugin.xpi plugin.zip
Method 3: If you have a program like WinRar, 7Zip, or something of your choice to open archived files then just open it through that program.
Then just extract the install.rdf file.
The install.rdf is a renamed .xml file, so any text editor will open it.
Once you have the install file open, look this xml node (should be towards the top):
<em:targetApplication>
<Description>
<em:id>{ec8030f7-c20a-464f-9b0e-13a3a9e97384}</em:id>
<em:minVersion>0.8</em:minVersion>
<em:maxVersion>3.6.*</em:maxVersion>
</Description>
</em:targetApplication>
(This was taken from LiveHttpHeaders-0.16)
em:targetApplication : Node for Firefox's application information
em:id : registry information
em:minVersion : lowest version of Firefox that this particular plugin can function on
em:maxVersion : highest version of Firefox that this particular plugin can function on (what we came here for. :))
Simply just change the maxVersion number the current version or use the wildcard feature to prep for further updates on Firefox until the new release of you plugin.
For example:
<em:maxVersion>3.6.*</em:maxVersion>
to
<em:maxVersion>4.*.*</em:maxVersion>
That's it.
I take no responsibility for any damage done to your computer or software while doing this as I assume you realize that this is only for educational purposes.
So if you are like me and you update to the latest Firefox to find that your plugins are not supported, you feel a little bummed out.
Well, there is a way to truly test whether or not your plugins are functional. If you don't know already, Firefox plugins are .xpi file extensions
that are really just .zip files. You can just rename your file to a zip file extension to see the goodies inside.
Method 1: If your computer shows the extensions on files then just: Right click >> rename >> clear out .xpi and replace with .zip
Method 2: If not the previous method, then maybe this: Open a terminal (console) >> navigate to the directory of the xpi file and use the rename command
i.e. Windows: rename plugin.xpi plugin.zip
Method 3: If you have a program like WinRar, 7Zip, or something of your choice to open archived files then just open it through that program.
Then just extract the install.rdf file.
The install.rdf is a renamed .xml file, so any text editor will open it.
Once you have the install file open, look this xml node (should be towards the top):
<em:targetApplication>
<Description>
<em:id>{ec8030f7-c20a-464f-9b0e-13a3a9e97384}</em:id>
<em:minVersion>0.8</em:minVersion>
<em:maxVersion>3.6.*</em:maxVersion>
</Description>
</em:targetApplication>
(This was taken from LiveHttpHeaders-0.16)
em:targetApplication : Node for Firefox's application information
em:id : registry information
em:minVersion : lowest version of Firefox that this particular plugin can function on
em:maxVersion : highest version of Firefox that this particular plugin can function on (what we came here for. :))
Simply just change the maxVersion number the current version or use the wildcard feature to prep for further updates on Firefox until the new release of you plugin.
For example:
<em:maxVersion>3.6.*</em:maxVersion>
to
<em:maxVersion>4.*.*</em:maxVersion>
That's it.
I take no responsibility for any damage done to your computer or software while doing this as I assume you realize that this is only for educational purposes.
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Thanks. 
