README.md in jsbundling-rails-0.1.2 vs README.md in jsbundling-rails-0.1.4

@@ -13,10 +13,10 @@
 You can configure your bundler options in the `build` script in `package.json` or via the installer-generated `rollup.config.js` for rollup.js or `webpack.config.json` for Webpack (esbuild does not have a default configuration format).
 
 
 ## Installation
 
-You must already have node and yarn installed on your system. Then:
+You must already have node and yarn installed on your system. You will also need npx version 7.1.0 or later. Then:
 
 1. Add `jsbundling-rails` to your Gemfile with `gem 'jsbundling-rails'`
 2. Run `./bin/bundle install`
 3. Run `./bin/rails javascript:install:[esbuild|rollup|webpack]`