pref("app.update.enabled", true); //enables or disables the background update checker; default=true
pref("app.update.auto", false); //enables background download of updates according to the policy described by app.update.mode; default=true
pref("app.update.mode", 2); //defines the policy by which background downloads are done; 0=download all; 1=download compatible; 2=download minor and prompt for major; default=1
pref("app.update.silent", false); //disables all notification UI for updates; default=false