diff --git a/package.json b/package.json
index df10b75..bece9ea 100644
--- a/package.json
+++ b/package.json
@@ -44,7 +44,7 @@
     "stemmer": "0.1.4"
   },
   "devDependencies": {
-    "chai": "3.5.0",
+    "chai": "4.0.1",
     "snyk": "1.14.3",
     "codecov": "1.0.1",
     "istanbul": "0.4.3",