diff --git a/package.json b/package.json
index 9978668..0c6ecc6 100644
--- a/package.json
+++ b/package.json
@@ -30,7 +30,7 @@
   "author": "Arnout Kazemier",
   "license": "MIT",
   "devDependencies": {
-    "assume": "~1.5.0",
+    "assume": "~2.0.0",
     "istanbul": "~0.4.5",
     "mocha": "~3.5.0",
     "pre-commit": "~1.2.0"