diff --git a/bower.json b/bower.json
index c5f46e9d8..69917682e 100644
--- a/bower.json
+++ b/bower.json
@@ -10,7 +10,7 @@
     "polymer": "Polymer/polymer#^1.2.0"
   },
   "devDependencies": {
-    "web-component-tester": "*"
+    "web-component-tester": "^4.0.0"
   },
   "ignore": []
 }