diff --git a/package.json b/package.json
index cb9ba2d1fb..1450413043 100644
--- a/package.json
+++ b/package.json
@@ -86,7 +86,7 @@
     "sinon": "1.14.1",
     "sinon-chai": "2.7.0",
     "stylus": "~0.54.5",
-    "terser-webpack-plugin": "^1.2.1",
+    "terser-webpack-plugin": "^1.2.2",
     "webpack": "^4.28.1",
     "webpack-cli": "^3.2.1",
     "webpack-manifest-plugin": "^2.0.4"
diff --git a/webpack.config.js b/webpack.config.js
index 9c41aeb10e..1f4a6877a0 100644
--- a/webpack.config.js
+++ b/webpack.config.js
@@ -24,6 +24,7 @@ const baseConfig = {
           // preserve identifier names for easier debugging & support
           mangle: false,
         },
+        parallel: false,
       }),
     ],
   },