diff --git a/package.json b/package.json
index 5495346..457d1ea 100644
--- a/package.json
+++ b/package.json
@@ -63,7 +63,7 @@
     "webpack": "^1.12.2"
   },
   "devDependencies": {
-    "chai": "^3.5.0",
+    "chai": "^4.0.1",
     "chai-http": "^3.0.0",
     "mocha": "^3.2.0",
     "nightwatch": "^0.9.12",