diff --git a/lib/mixins/element-mixin.js b/lib/mixins/element-mixin.js
index a8dbc8ab14..8ba0fab5a4 100644
--- a/lib/mixins/element-mixin.js
+++ b/lib/mixins/element-mixin.js
@@ -673,7 +673,7 @@ export const ElementMixin = dedupingMixin(base => {
         if (dom) {
           if (!n.shadowRoot) {
             if (window.ShadyDOM) {
-              ShadyDOM.upgrade(dom, this, {mode: 'open'});
+              ShadyDOM['attachDom'](dom, this, {mode: 'open'});
             } else {
               n.attachShadow({mode: 'open'});
               n.shadowRoot.appendChild(dom);