diff --git a/package.json b/package.json
index 3fecf43..69b63de 100644
--- a/package.json
+++ b/package.json
@@ -13,7 +13,7 @@
   },
   "devDependencies": {
     "chai": "4.2.0",
-    "koa": "2.5.3",
+    "koa": "2.16.4",
     "mocha": "2.5.3",
     "supertest": "3.2.0"
   }