How do you update Firefox and fix the certificate error?
Older Firefox builds hit an expired Mozilla root certificate that disables add-ons; the update takes only a few minutes.
Short answer
Open Firefox, click the three-line menu at the top right, then go to Help > About Firefox. The window starts downloading the update on its own, and once it finishes you press "Restart to update Firefox". As soon as your version reads 128 or newer (115.13 or newer on ESR), the root certificate problem is gone.
What you need
Step by step
Check your current version
Open Firefox and click the three-line menu button at the top right. Follow Help > About Firefox. The window that opens shows your version number, and anything below 128 needs updating.
Download the update
The moment the About Firefox window opens, it checks for updates and starts the download by itself. Leave the window open until the download finishes. Depending on your connection this takes anywhere from a few seconds to a few minutes.
Restart the browser
When the download completes, a "Restart to update Firefox" button appears. Click it; Firefox closes, reopens, and restores your open tabs. The update is not finished until this restart happens.
Verify the version
Go back to menu > Help > About Firefox and confirm the number is 128 or higher. If your workplace uses the enterprise ESR build, 115.13 or higher is enough to clear the issue.
Review your add-ons
Open menu > Add-ons and themes. If any extensions were switched off because of the certificate, flip the toggle next to them back on. For anything still not working, remove it and install it again.
Turn on automatic updates
Go to menu > Settings > General and scroll to the bottom to find the Firefox Updates section. Select "Automatically install updates". That way the same problem will not catch you a second time.
Update Firefox on your phone
Open Google Play Store on Android or the App Store on iPhone and search for Firefox. Tap "Update" if the button is showing. Mobile versions update through the store, so no separate certificate step is required.
Tips
Watch out
Do not download Firefox from unofficial sites to "fix" the certificate problem. Fake installers can steal your saved passwords. Download only from mozilla.org or your phone's official app store.
Frequently asked questions
+What happens if I do not update?
Add-ons and themes get disabled because they cannot be verified, DRM-protected video services may fail to play, and the browser stops receiving new security patches.
+Which version is enough?
Firefox 128 or newer clears the problem for regular users, and 115.13 or newer does the same for anyone on the enterprise ESR build.
+Will the update erase my tabs and passwords?
No. Firefox restores your open tabs when it restarts, and saved passwords and bookmarks stay in your profile.
+I use Windows 7, can I move to version 128?
No, Firefox 128 does not support Windows 7 or 8. On those systems you need ESR 115.13 or newer instead.
+Is there a different step for users in Turkey?
No. The Firefox update works the same way from inside the browser in every country, with no extra agency or application involved.
Sources and verification
Last verified: 13 Eylül 2026. tell us.
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