diff --git a/app/polymer/package.json b/app/polymer/package.json
index d6e2435e99c9..ccbf46a702ed 100644
--- a/app/polymer/package.json
+++ b/app/polymer/package.json
@@ -41,7 +41,7 @@
     "babel-runtime": "^6.26.0",
     "case-sensitive-paths-webpack-plugin": "^2.1.2",
     "common-tags": "^1.4.0",
-    "copy-webpack-plugin": "^4.5.1",
+    "copy-webpack-plugin": "^5.0.0",
     "core-js": "^2.5.1",
     "dotenv-webpack": "^1.5.5",
     "find-cache-dir": "^1.0.0",
@@ -52,7 +52,7 @@
     "react-dev-utils": "^5.0.0",
     "react-dom": "^16.0.0",
     "redux": "^3.7.2",
-    "uglifyjs-webpack-plugin": "^1.2.3",
+    "uglifyjs-webpack-plugin": "^2.0.0",
     "util-deprecate": "^1.0.2",
     "webpack": "^3.11.0",
     "webpack-hot-middleware": "^2.21.2"