diff --git a/09-Optimizing-Performance/source/async-opt/package.json b/09-Optimizing-Performance/source/async-opt/package.json
index fc82b7b..591da42 100644
--- a/09-Optimizing-Performance/source/async-opt/package.json
+++ b/09-Optimizing-Performance/source/async-opt/package.json
@@ -12,6 +12,6 @@
     "express": "^4.14.0",
     "fastq": "^1.4.1",
     "lru-cache": "^4.0.1",
-    "mongodb": "^2.1.18"
+    "mongodb": "^3.6.1"
   }
 }