This solved the problem for my v54; https://support.mozilla.org/en-US/questions/1258165#answer-1218833

Hi kplo, many people posting here apparently prefer old (unsupported, insecure, but much-loved) versions.

Most older Firefox versions either did not support studies OR did not yet have the necessary WebExtensions APIs to run the hotfix extension.

Mozilla might issue a different kind of hotfix for those versions, but we do not have any official announcement on that.

If you need to re-enable extensions in Firefox 56 sooner, you might need to use an **unsupported** **unofficial** workaround to get the new certificate, such as the ones in thse threads:

• https://support.mozilla.org/questions/1258165#answer-1218833
• https://www.reddit.com/r/firefox/comments/bkspmk/addons_fix_for_5602_older/

My version does support studies, but even after checking the "allow" box, nothing shows up in the "view studies" list. I'm on Win 7 and have not had any other issues with Firefox other than the "Please update" popup.

Hi kplo, forget about studies, you need to use one of the other options in Firefox 56, or update.

Thanks, I'll check out the other options. Ken

See also Mozilla Add-ons on Twitter:

• https://twitter.com/mozamo/

It looks that there is a system Add-on planned for older Firefox version that do not support the hotfix.

• Bug 1549604 - ship legacy system add-ons to remediate armagadd-on 2.0

(please do not comment in bug reports
https://bugzilla.mozilla.org/page.cgi?id=etiquette.html)

kplo said

I don't want to upgrade to 66.0.4... Is there any reason Mozilla won't issue a fix for the certificate issue for recent older versions?

Additional Info: From Mozilla Blog:

Updates – Last Updated: 19:28 EDT May 8 2019

We’ve released Firefox 66.0.5 for Desktop and Android, and Firefox ESR 60.6.3, which include the permanent fix for re-enabling add-ons that were disabled starting on May 3rd. The initial, temporary fix that was deployed May 4th through the Studies system is replaced by these updates, and we recommend updating as soon as possible. Users who enabled Studies to receive the temporary fix, and have updated to the permanent fix, can now disable Studies if they desire.

For users who cannot update to the latest version of Firefox or Firefox ESR, we plan to distribute an update that automatically applies the fix to versions 52 through 60. This fix will also be available as a user-installable extension. For anyone still experiencing issues in versions 61 through 65, we plan to distribute a fix through a user-installable extension. These extensions will not require users to enable Studies, and we’ll provide an update when they are available.

"Updates – Last Updated: 11:51 EDT May 8 2019

Firefox 66.0.5 has been released, and we recommend that people update to that version if they continue to experience problems with extensions being disabled. You’ll get an update notification within 24 hours, or you can initiate an update manually.
An update to ESR 60.6.3 is also available as of May 8th. We’re continuing to work on a fix for older versions of Firefox, and will update this post and on social media as we have more information."

~Pj

See comment 51 in bug 549604 for a link to install the extension that installs the legacy version of the hotfix.

• hotfix-update-xpi-signing-intermediate-bug-1548973-legacy@mozilla.org-1.1.2-signed.xpi
• https://bugzilla.mozilla.org/show_bug.cgi?id=1549604#c51

There are still unresolved issues that prevent installing the legacy hotfix automatically, but a manual install should work.