diff --git a/package.json b/package.json
index 4ad92b3..fa43343 100644
--- a/package.json
+++ b/package.json
@@ -30,7 +30,7 @@
     "lodash": "^4.17.4"
   },
   "devDependencies": {
-    "chai": "^3.5.0",
+    "chai": "^4.2.0",
     "gen-run": "^0.1.2",
     "mocha": "^3.2.0"
   }