Updating Firefox is extremely important because the updates include various security and privacy fixes. If you run an older version of Firefox, you are vulnerable to all sorts of known security threats. It's never recommended.

If you want to receive less of the feature updates, but still get the security patches, perhaps Firefox ESR is the best option for you. The front-end of this version of Firefox is changed far less frequently, but it still receives the same security and privacy fixes that the regular version of Firefox does.

Hope this helps.

Thank you for the advice. Funny, but I have never been hacked using Firefox, or Netscape. Never had a security issue. I may try your suggestion. Thank you.

It's much like leaving your car unlocked with the keys in the ignition. You may do it all of the time with no consequences, but it only takes one time and then you will be visiting the car dealership.

Generally, by the time that security holes are fixed in an update, the issues are well documented. Therefore, it's pretty easy for attackers to take advantage of people who haven't been keeping up with updates regularly.

So you never answered the question. How can I disable the update notification process with these newer levels of Firefox? Is going back to 59.0 level the only way possible?

Bradford Caslon said

So you never answered the question. How can I disable the update notification process with these newer levels of Firefox? Is going back to 59.0 level the only way possible?

To disable updates in Firefox, you need to use the DisableAppUpdate policy via Windows Group Policy or a policies.json file.

Hope this helps.