diff --git a/package.json b/package.json
index 83742f8922..d12b9ba18a 100644
--- a/package.json
+++ b/package.json
@@ -27,7 +27,7 @@
     "build:umd:min": "cross-env BABEL_ENV=commonjs NODE_ENV=production webpack src/index.js dist/redux.min.js",
     "build:examples": "cross-env BABEL_ENV=commonjs babel-node examples/buildAll.js",
     "build": "npm run build:commonjs && npm run build:es && npm run build:umd && npm run build:umd:min",
-    "prepublish": "npm run clean && npm run check:src && npm run build",
+    "prepublish": "npm run clean && npm run check:src && npm run build && check-es3-syntax lib/ dist/ --kill",
     "docs:clean": "rimraf _book",
     "docs:prepare": "gitbook install",
     "docs:build": "npm run docs:prepare && gitbook build -g reactjs/redux",
@@ -93,6 +93,7 @@
     "babel-plugin-transform-es3-property-literals": "^6.5.0",
     "babel-plugin-transform-object-rest-spread": "^6.3.13",
     "babel-register": "^6.3.13",
+    "check-es3-syntax-cli": "0.0.2",
     "cross-env": "^1.0.7",
     "eslint": "^1.10.3",
     "eslint-config-rackt": "^1.1.1",
diff --git a/webpack.config.js b/webpack.config.js
index 2c37a269fd..3ce84f94bc 100644
--- a/webpack.config.js
+++ b/webpack.config.js
@@ -28,7 +28,6 @@ if (env === 'production') {
         pure_getters: true,
         unsafe: true,
         unsafe_comps: true,
-        screw_ie8: true,
         warnings: false
       }
     })