diff --git a/package.json b/package.json
index 38e8450..70ebc56 100644
--- a/package.json
+++ b/package.json
@@ -2,6 +2,9 @@
   "name": "volleyball",
   "version": "1.0.0",
   "description": "🏐 Tiny HTTP logger for Express showing asynchronous requests and responses",
+  "engines" : {
+    "node" : "^6.0.0"
+  },
   "homepage": "https://github.com/glebec/volleyball",
   "main": "lib/volleyball.js",
   "scripts": {