diff --git a/challenges/01-front-end-development-certification/intermediate-bonfires.json b/challenges/01-front-end-development-certification/intermediate-bonfires.json
index 02a91ad0ce..5b903962de 100644
--- a/challenges/01-front-end-development-certification/intermediate-bonfires.json
+++ b/challenges/01-front-end-development-certification/intermediate-bonfires.json
@@ -341,7 +341,7 @@
         "Array.prototype.indexOf()",
         "Array.prototype.push()",
         "Array.prototype.join()",
-        "String.prototype.substr()",
+        "String.prototype.substring()",
         "String.prototype.split()"
       ],
       "isRequired": true,