diff --git a/package.json b/package.json
index ae785cc..0548e32 100644
--- a/package.json
+++ b/package.json
@@ -27,7 +27,7 @@
   },
   "homepage": "https://github.com/unshiftio/xhr-send",
   "devDependencies": {
-    "assume": "~1.5.0",
+    "assume": "~2.0.0",
     "istanbul": "~0.4.5",
     "mocha": "~3.5.0",
     "pre-commit": "~1.2.0"