diff --git a/package.json b/package.json
index abacbad..d24e018 100644
--- a/package.json
+++ b/package.json
@@ -11,7 +11,7 @@
     "send": "0.13.0"
   },
   "devDependencies": {
-    "istanbul": "0.3.9",
+    "istanbul": "0.4.0",
     "mocha": "2.2.5",
     "supertest": "1.0.1"
   },