diff --git a/package.json b/package.json
index cb02a15..8c22196 100644
--- a/package.json
+++ b/package.json
@@ -16,7 +16,7 @@
     "twilio": "~3.0.0"
   },
   "devDependencies": {
-    "chai": "^3.5.0",
+    "chai": "^4.3.4",
     "cheerio": "^0.22.0",
     "eslint": "^3.19.0",
     "eslint-config-google": "^0.7.1",