Expired Mozilla Root Certificate - Use old add-ons without browser update!

[sandalik]

If you’ve been using an old version of the Mozilla Firefox browser, you might have seen a warning to update it before March 13, 2025. You can find more information here: https://support.mozilla.org/en-US/kb/root-certificate-expiration?pubDate=20250313.

It's important to use updated browsers, but many developers still depend on old add-ons that aren’t available for the latest versions.

Mozilla is pushing users to upgrade Firefox because of the expiring Root Certificate, but some believe this is really about collecting user data for advertising or AI training, which newer versions can do but older ones cannot. At least not without updated Terms and Conditions! There are already many discussions online about how the new terms and conditions for updated Firefox versions may compromise user privacy, so I won’t go into that further.

If you understand the security risks but need to keep using an old browser for specific reasons, there’s an easy fix. You can take the Root Certificate from a newer Firefox version and put it into the profile folder of your old version. This way, your add-ons and extensions will still work because the Root Certificate will be valid! You won’t need to update the Firefox browser itself!

HOW TO UPDATE ROOT CERTIFICATE IN FIREFOX:

1. Search the Profile folder of a newer version of Firefox browser (v128+ or v115.13+ ESR) for the cert9.db file. Save this file. This contains the Root Certificate.
2. Now overwrite the cert9.db from the Profile folder of the older version of Firefox browser the the newer version of the cert9.db file.

Now you will see that the add-ons will work again as expected in the older version of the browser also!
Attached is the newer version of the cert9.db file for the lazier folks... Just swap it with the old version in the firefox profile folder