diff --git a/content/docs/add-react-to-an-existing-app.md b/content/docs/add-react-to-an-existing-app.md
index 8a6cf3f0..9c584d2b 100644
--- a/content/docs/add-react-to-an-existing-app.md
+++ b/content/docs/add-react-to-an-existing-app.md
@@ -40,6 +40,10 @@ npm install --save react react-dom
 
 Both Yarn and npm download packages from the [npm registry](http://npmjs.com/).
 
+>  Note:
+>
+>  To prevent potential incompatibilities, all react packages should use the same version. (This includes `react`, `react-dom`, `react-test-renderer`, etc.)
+
 ### Enabling ES6 and JSX
 
 We recommend using React with [Babel](http://babeljs.io/) to let you use ES6 and JSX in your JavaScript code. ES6 is a set of modern JavaScript features that make development easier, and JSX is an extension to the JavaScript language that works nicely with React.