Here’s a few things that are new, but “don’t feel pressured to upgrade anything.”

• 🎉 More styling options: you can use Sass and CSS Modules out of the box.
• 🐠 We updated to Babel 7, including support for the React fragment syntax and many bugfixes.
• 📦 We updated to webpack 4, which automatically splits JS bundles more intelligently.
• 🃏 We updated to Jest 23, which includes an interactive mode for reviewing snapshots.
• …plus 7 more updates…