I have tried the following solutions: #nano /usr/lib/firefox/defaults/pref/channel-prefs.js #nano /usr/lib/firefox/browser/defaults/preferences/nano syspref.js #nano /usr/lib/firefox/browser/defaults/preferences/user.js commented out this: //pref("app.update.channel", "release"); and entered the following: pref("app.update.enabled", false); pref("app.update.silent", false); I also created a profile folder in ~/.mozilla and added a text files with these: // turn off application updates: user_pref("app.update.enabled", false); I also tried to block mozilla.org from iptables but that didn't help either. Please help me stop automatic updates. We need to be using version 28. Thanks!