diff --git a/package.json b/package.json
index a556b67..93b0e39 100644
--- a/package.json
+++ b/package.json
@@ -50,7 +50,7 @@
     "istanbul": "0.4.4",
     "isparta": "^4.0.0",
     "js-beautify": "^1.6.2",
-    "mocha": "^2.4.5"
+    "mocha": "^3.4.1"
   },
   "keywords": [
     "constraint solving",