diff --git a/package.json b/package.json
index 8adc988..249ab81 100644
--- a/package.json
+++ b/package.json
@@ -32,7 +32,7 @@
   },
   "devDependencies": {
     "chai-passport-strategy": "~1.0.0",
-    "chai": "~3.5.0",
+    "chai": "~4.2.0",
     "mocha": "~3.0.2",
     "check-build": "*"
   }