diff --git a/lib/metadata.js b/lib/metadata.js
index 9b0340f86..419780d7b 100644
--- a/lib/metadata.js
+++ b/lib/metadata.js
@@ -70,7 +70,7 @@ commands.RESET_OWNERS = function (meta, args) {
 };
 
 commands.UPDATE_EXPIRATION = function () {
-
+    throw new Error("E_NOT_IMPLEMENTED");
 };
 
 var handleCommand = function (meta, line) {