diff --git a/package.json b/package.json
index 12935e3..3aec06c 100644
--- a/package.json
+++ b/package.json
@@ -44,7 +44,7 @@
     "chai-as-promised": "^7.1.1",
     "codecov": "^3.0.2",
     "mocha": "^5.2.0",
-    "np": "^3.0.1",
+    "np": "^5.1.1",
     "nyc": "^12.0.1",
     "prettier": "^1.13.3",
     "proptest": "0.0.4",