diff --git a/package.json b/package.json
index db57efc..df8c36d 100644
--- a/package.json
+++ b/package.json
@@ -38,6 +38,6 @@
     "unexpected-http": "4.0.0",
     "mocha-lcov-reporter": "0.0.2",
     "coveralls": "2.11.4",
-    "istanbul": "0.3.22"
+    "istanbul": "0.4.0"
   }
 }