diff --git a/package.json b/package.json
index ad6d3ea..809bd53 100644
--- a/package.json
+++ b/package.json
@@ -35,7 +35,7 @@
   },
   "devDependencies": {
     "@satazor/eslint-config": "^3.0.0",
-    "chai": "^3.4.1",
+    "chai": "^4.0.0",
     "coveralls": "^2.11.6",
     "eslint": "^3.0.0",
     "istanbul": "^0.4.1",