--- a/mobile/android/app/mobile.js
+++ b/mobile/android/app/mobile.js
@@ -183,17 +183,17 @@ pref("dom.experimental_forms", true);
 pref("dom.forms.number", true);
 
 /* extension manager and xpinstall */
 pref("xpinstall.whitelist.directRequest", false);
 pref("xpinstall.whitelist.fileRequest", false);
 pref("xpinstall.whitelist.add", "https://addons.mozilla.org");
 pref("xpinstall.whitelist.add.180", "https://marketplace.firefox.com");
 
-pref("xpinstall.signatures.required", false);
+pref("xpinstall.signatures.required", true);
 
 pref("extensions.enabledScopes", 1);
 pref("extensions.autoupdate.enabled", true);
 pref("extensions.autoupdate.interval", 86400);
 pref("extensions.update.enabled", true);
 pref("extensions.update.interval", 86400);
 pref("extensions.dss.enabled", false);
 pref("extensions.dss.switchPending", false);