{
    "AppAutoUpdate": false,
    "DisableAppUpdate": true,
    "DisableTelemetry": true
   }

I am using Firefox on an old Ubuntu machine, and found myself unable to disable the auto update feature of Firefox. I understand why Firefox wants to do auto update, but for me personally it's negatively impacting my productivity. Many times I was looking up reference materials only to be told that I need to restart Firefox because it just updated itself. Imagine how frustrating it is, especially when I use the Private Browsing mode a lot to avoid having to clean up browsing history and cached files later. All in all, while the auto update feature might be good for some users, it's just not working for me, so I want it to be disabled. I tried a couple of things. First, there's nothing in the "Preferences" page related to the auto update. Second, I tried to change the value of "app.update.auto" in the "about:config" page to false, and it still does auto update. Finally, I tried to add a "policies.json" file to "/etc/firefox/", with the following content: { "policies": { "AppAutoUpdate": false, "DisableAppUpdate": true, "DisableTelemetry": true } } Yet it still does auto updates. As a matter of fact, it updated itself to version 80 just now. This driving me crazy. Any useful suggestions will be sincerely appreciated.