diff --git a/package.json b/package.json
index b0c5a1e..dd79994 100644
--- a/package.json
+++ b/package.json
@@ -44,7 +44,7 @@
   },
   "devDependencies": {
     "babel": "^5.0.0",
-    "istanbul": "^0.3.22",
+    "istanbul": "^0.4.0",
     "make-lint": "^1.0.1",
     "mocha": "^2.0.1",
     "should": "^6.0.3",