Firefox Extension Compatibility: Hacking Files for Version Support

Addressing Firefox Extension Compatibility Issues

A common challenge encountered when using Firefox involves extension compatibility following a major version update. Whether dealing with a newly discovered extension or a long-standing favorite, there's a method to restore functionality to those extensions.

Several reasons might lead you to choose this approach for resolving extension incompatibility:

• You are hesitant to modify the “about:config” settings directly.
• You prefer to preserve the default “about:config” settings and maintain active compatibility checks.
• You are interested in demonstrating technical proficiency.

It’s important to remember that most extensions function seamlessly with new Firefox versions, often only requiring an update to the “version compatibility number”. However, occasionally, an extension may necessitate adjustments by its developer.

Identifying the Problem

The following message represents a frequently seen, and unwelcome, notification when attempting to use a favored extension – or a new one – after a fresh installation.

Note: This technique is also effective for replacing incompatible extensions already installed during a browser upgrade.

Modifying the XPI File

This process requires manually downloading the extension to your computer. Right-click the extension's "Install Button" and select "Save As" to begin.

Once downloaded, you can proceed with modifying the extension’s files.

For this example, we’ll use the “GCal Popup Extension”. It’s best to place the extension in a new folder, such as on your Desktop, and then unzip it as you would any standard zip file.

Note: A reader, Dante, highlighted that if you lack a third-party zip utility like IZArc or 7-Zip, changing the ".xpi" file extension to ".zip" allows you to utilize Windows’ built-in zip software.

After unzipping, you’ll see the various folders and files contained within the “xpi file”. The number of files will vary depending on the extension. Focus on a single file: the “install.rdf” file.

Note: Before proceeding, move the original extension file to a separate location to prevent confusion.

Open the “install.rdf” file in “Notepad” to modify the “maxVersion” number.

In our case, the number was listed as “3.5.*”, and we needed to increase it.

Replacing the “5” with a “7” was sufficient. Save the file after entering the new “maxVersion” number.

Next, re-zip all the files into a single archive. Ensure you create a file with the “.zip” extension; otherwise, the process will fail.

Once the new zip file is created, rename it, including the file extension. We copied and pasted the original extension name for our example.

After changing the name, click outside the “text area”. A confirmation message will appear; click “Yes” to finalize the process.

Your modified extension is now ready for installation.

Drag the extension into your browser to install it, and you’ll see the message “Restart to complete the installation.”

Upon restarting your browser, check the “Add-ons Manager Window” to verify the extension’s version compatibility numbers.

Your extension should now be functioning correctly.

In Conclusion

This method provides a solution if you wish to explore a new approach, demonstrate technical skill, or maintain a pristine Firefox installation. It should successfully restore functionality to your desired extensions.