diff --git a/package.json b/package.json
index c72938d..6e80f04 100644
--- a/package.json
+++ b/package.json
@@ -44,7 +44,7 @@
     "mocha": "^5.0.0",
     "sax": "^1.2.4",
     "should": "^13.2.1",
-    "sinon": "^6.0.0"
+    "sinon": "^9.0.1"
   },
   "scripts": {
     "test": "node test-runner.js",