Upgrading from react scripts 3.4 to 4 - how does it work?

[RobertDanielsson]

I followed the instructions to upgrade react-scripts from 3.4 to 4 (yarn add --exact [email protected]), however i'm confused as to how this works. It only changes one line in my package.json file, react-scripts 3.4 to 4. My other packages such as react, react-dom, jest, testing-library/react etc are still on the same version as before since the command doesn't touch them.

Am i supposed to upgrade these packages manually in my package.json or how do i correctly handle this migration?

Second question:
Our project uses Material-UI 4 which is supports react 16 and not 17 (material-ui 5 is in alpha and supports react 17). Can we upgrade to react-scripts 4 and stay on React 16? Will this give us fast refresh functionality for example?

[ChristianMurphy]

Am i supposed to upgrade these packages manually in my package.json[?]

yes

Our project uses Material-UI 4 which is supports react 16 and not 17 (material-ui 5 is in alpha and supports react 17). Can we upgrade to react-scripts 4 and stay on React 16?

also yes

Will this give us fast refresh functionality for example?

yes