diff --git a/lib/elements/dom-module.html b/lib/elements/dom-module.html
index 3ca593b1a9..1ec92aff91 100644
--- a/lib/elements/dom-module.html
+++ b/lib/elements/dom-module.html
@@ -78,9 +78,10 @@
      * @param {string} name Name of attribute.
      * @param {?string} old Old value of attribute.
      * @param {?string} value Current value of attribute.
+     * @param {?string} namespace Attribute namespace.
      * @return {void}
      */
-    attributeChangedCallback(name, old, value) {
+    attributeChangedCallback(name, old, value, namespace) {
       if (old !== value) {
         this.register();
       }
diff --git a/lib/legacy/legacy-element-mixin.html b/lib/legacy/legacy-element-mixin.html
index 7306c65140..6c2045f155 100644
--- a/lib/legacy/legacy-element-mixin.html
+++ b/lib/legacy/legacy-element-mixin.html
@@ -137,12 +137,13 @@
        * @param {string} name Name of attribute.
        * @param {?string} old Old value of attribute.
        * @param {?string} value Current value of attribute.
+       * @param {?string} namespace Attribute namespace.
        * @return {void}
        * @override
        */
-      attributeChangedCallback(name, old, value) {
+      attributeChangedCallback(name, old, value, namespace) {
         if (old !== value) {
-          super.attributeChangedCallback(name, old, value);
+          super.attributeChangedCallback(name, old, value, namespace);
           this.attributeChanged(name, old, value);
         }
       }
diff --git a/lib/mixins/disable-upgrade-mixin.html b/lib/mixins/disable-upgrade-mixin.html
index a94418214e..f714325de5 100644
--- a/lib/mixins/disable-upgrade-mixin.html
+++ b/lib/mixins/disable-upgrade-mixin.html
@@ -60,13 +60,13 @@
       }
 
       /** @override */
-      attributeChangedCallback(name, old, value) {
+      attributeChangedCallback(name, old, value, namespace) {
         if (name == DISABLED_ATTR) {
           if (!this.__dataEnabled && value == null && this.isConnected) {
             super.connectedCallback();
           }
         } else {
-          super.attributeChangedCallback(name, old, value);
+          super.attributeChangedCallback(name, old, value, namespace);
         }
       }
 
@@ -113,4 +113,4 @@
 
 })();
 
-</script>
\ No newline at end of file
+</script>
diff --git a/lib/mixins/properties-changed.html b/lib/mixins/properties-changed.html
index 000c1374af..cfde2854cc 100644
--- a/lib/mixins/properties-changed.html
+++ b/lib/mixins/properties-changed.html
@@ -407,15 +407,16 @@
          * @param {string} name Name of attribute that changed
          * @param {?string} old Old attribute value
          * @param {?string} value New attribute value
+         * @param {?string} namespace Attribute namespace.
          * @return {void}
          * @suppress {missingProperties} Super may or may not implement the callback
          */
-        attributeChangedCallback(name, old, value) {
+        attributeChangedCallback(name, old, value, namespace) {
           if (old !== value) {
             this._attributeToProperty(name, value);
           }
           if (super.attributeChangedCallback) {
-            super.attributeChangedCallback(name, old, value);
+            super.attributeChangedCallback(name, old, value, namespace);
           }
         }
 
diff --git a/test/smoke/behavior-mixin.html b/test/smoke/behavior-mixin.html
index 6c9ed28d7b..b604821080 100644
--- a/test/smoke/behavior-mixin.html
+++ b/test/smoke/behavior-mixin.html
@@ -22,6 +22,7 @@
   </template>
 </dom-module>
 <script>
+  /** @polymerBehavior */
   var MyBehavior = {
     properties: {
       behaviorProp: {
@@ -37,6 +38,7 @@
     }
   }
 
+  /** @polymerBehavior */
   var MyBehavior2 = {
     ready: function() {
       console.log(this.localName, 'MyBehavior2.ready');