diff --git a/package.json b/package.json
index 14b5b9ae48..66837ec4f4 100644
--- a/package.json
+++ b/package.json
@@ -1,7 +1,7 @@
 {
   "name": "6to5",
   "description": "Turn ES6 code into vanilla ES5 with source maps and no runtime",
-  "version": "1.3.0",
+  "version": "1.3.1",
   "author": "Sebastian McKenzie <sebmck@gmail.com>",
   "homepage": "https://github.com/sebmck/6to5",
   "repository": {
@@ -45,7 +45,8 @@
     "fs-readdir-recursive": "0.0.2",
     "lodash": "2.4.1",
     "mkdirp": "0.5.0",
-    "es6-shim": "^0.18.0"
+    "es6-shim": "^0.18.0",
+    "es6-symbol": "^0.1.1"
   },
   "devDependencies": {
     "es6-transpiler": "0.7.17",