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Topic #6

React Upgrade

React evolves with new versions that change syntax and tooling, so staying current matters. Learn the upgrade path and what changed in recent releases.


Upgrade to React 19

Upgrading an existing React application to version 19 only requires two steps.

Note: If you are already using the latest version of React, you can skip this section.


Step 1: Install React 19

To install the latest version, from your project folder run the following from the terminal:

npm i react@latest react-dom@latest

Step 2: Use the new root API

In order to take advantage of React 19's concurrent features you'll need to use the new root API for client rendering.

// Before
import ReactDOM from 'react-dom';

ReactDOM.render(
  <h1>Hello React!</h1>,
  document.getElementById('root')
);

// After
import { createRoot } from 'react-dom/client';

createRoot(document.getElementById('root')).render(
  <h1>Hello React!</h1>
);

Note: Your application will work without using the new root API. If you continue to use ReactDOM.render your application will behave like React 17.

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React Upgrade – FAQs

Quick answers about learning React Upgrade in React.

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