diff --git a/package.json b/package.json
index 6f785b38..53b4bea1 100644
--- a/package.json
+++ b/package.json
@@ -17,7 +17,7 @@
     "vary": "~1.0.1"
   },
   "devDependencies": {
-    "istanbul": "0.3.17",
+    "istanbul": "0.3.20",
     "mocha": "2.2.5",
     "supertest": "1.0.1"
   },