diff --git a/package.json b/package.json
index ed904a2..e1036c0 100644
--- a/package.json
+++ b/package.json
@@ -35,7 +35,7 @@
     "react-dom": "^15.4.0"
   },
   "devDependencies": {
-    "assume": "~1.5.0",
+    "assume": "~2.0.0",
     "istanbul": "~0.4.5",
     "mocha": "~3.1.2",
     "pre-commit": "~1.2.0"