diff --git a/tambo_en.html b/tambo_en.html
index 30afc55d..44bad557 100644
--- a/tambo_en.html
+++ b/tambo_en.html
@@ -27,7 +27,7 @@
 
   // Preloads, with more included for phet-io brand
   let preloads = [
-    '../phet-core/js/phet-polyfill.js',
+    '../sherpa/lib/mdn-array-from-polyfill.js',
     '../joist/js/splash.js',
     '../sherpa/lib/jquery-2.1.0.js',
     '../sherpa/lib/lodash-4.17.4.js',