diff --git a/package.json b/package.json
index 57fdf7f..331903a 100644
--- a/package.json
+++ b/package.json
@@ -16,7 +16,8 @@
     "util-extend": "^1.0.1",
     "concat-stream": "^1.4.6",
     "bluebird": "^2.1.3",
-    "duplex-combination": "^1.0.1"
+    "duplex-combination": "^1.0.1",
+    "shallow-copy": "0.0.1"
   },
   "main": "index.js",
   "license": "BSD",