Idea - Hot reloading

To enable hot reloading, you need to disable safe write. See Web - (Hot|Live) (Edit|Reload) - Auto File Sync

Update

See Change Log: Change Log

Normally:

# Upgrade the script
npm install --save-dev --save-exact [email protected]
# Upgrade the app
npm install -g create-react-app

Library

https://www.npmjs.com/package/react-dev-utils - utilities