diff --git a/package.json b/package.json
index 85fdec56..e956b63d 100644
--- a/package.json
+++ b/package.json
@@ -31,6 +31,7 @@
     "heroku-postbuild": "yarn run build"
   },
   "engines": {
-    "node": "6.9.4"
+    "node": "6.9.4",
+    "yarn": "0.19.1"
   }
 }