Why React Upgrades Matter

React is one of the most widely used frontend libraries in modern web development. The team behind React actively releases new features, performance improvements, and bug fixes—but to take advantage of them, your project must be on the latest version.

Upgrading React ensures:

• Improved performance and efficiency

• Access to new hooks or APIs (like useId in React 18)

• Better developer tools

• Security patches and stability improvements

However, upgrading React isn’t just a version bump. Without care, it can lead to broken apps, deprecated code, or UI bugs.

When Should You Upgrade React?

Step-by-Step Guide to Upgrade React

Here’s how to safely upgrade React in an existing project.

✅ 1. Check Current React Version

Use the terminal:

npm list react react-dom

Or check your package.json:

"dependencies": {
  "react": "^17.0.2",
  "react-dom": "^17.0.2"
}

✅ 2. Review the Official React Release Notes

Check: React Releases

Take note of:

• Breaking changes

• Deprecated methods

• New features

✅ 3. Update react and react-dom

Use npm:

npm install react@latest react-dom@latest

Or with yarn:

yarn add react@latest react-dom@latest

Pro Tip: Use exact versions for production-grade apps.

✅ 4. Update Supporting Libraries (Optional but Recommended)

Make sure the following libraries are compatible with your React version:

• react-scripts (for CRA apps)

• react-router-dom

• redux/react-redux

• react-testing-library

• @types/react (if using TypeScript)

Use the following command to check outdated packages:

npm outdated

✅ 5. Run Lint and Tests

Before running your app:

• Fix warnings or breaking changes

• Run your test suite (Jest, Vitest, etc.)

• Look for deprecated methods like componentWillMount

Common Breaking Changes in React 18

React 18 Entry Point Change

Replace:

ReactDOM.render(<App />, document.getElementById('root'));

With:

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

const root = createRoot(document.getElementById('root'));
root.render(<App />);

Functional Code Example: React 18 Migration

// index.js (React 18 version)
import React from 'react';
import { createRoot } from 'react-dom/client';
import App from './App';

const container = document.getElementById('root');
const root = createRoot(container); // New in React 18
root.render(<App />);

// App.js
import React, { useState } from 'react';

function App() {
  const [count, setCount] = useState(0);

  return (
    <div style={{ padding: 20 }}>
      <h1>React Upgrade Demo</h1>
      <p>Clicked {count} times</p>
      <button onClick={() => setCount(prev => prev + 1)}>Click Me</button>
    </div>
  );
}

export default App;

Tips & Common Pitfalls

✅ Best Practices

• Use createRoot() in React 18 instead of ReactDOM.render()

• Update peer dependencies (like TypeScript types)

• Refactor deprecated lifecycle methods (e.g., componentWillMount)

• Use static code analysis tools like ESLint or React DevTools

⚠️ Watch Out For

• Breaking changes in third-party packages

• Component behavior changes due to automatic batching

• Conflicts with legacy React features

React Upgrade Tools

Conclusion: Keep Your React App Future-Proof

Upgrading React may seem intimidating, but it pays off in terms of performance, developer experience, and access to modern features.

Actionable Tips:

• Stay on top of React release notes.

• Use a dev/test branch to trial upgrades.

• Use linters, TypeScript, and automated tests to catch issues early.

• Upgrade incrementally and document the changes.

By following the above checklist, you’ll ensure your React app remains stable, secure, and ready for what’s next.