Migrating Next app from Full SSR to hybrid SSR/SSG - When should we use "getInitialProps"?

[Vadorequest]

Since 9.3, 3 new utility functions are available.

https://nextjs.org/docs/basic-features/data-fetching

But getInitialProps is mentioned nowhere. Is it meant not to be used anymore (in newer projects)? Or is it still useful for some use cases?

I'm in the process of migrating a Next.js app that uses getInitialProps in _app (SSR enabled for every page) to a hybrid app with per-page SSG/SSR. I'm not exactly sure what to do.

Also, does _app supports getStaticProps, or must it be added for each page? It's not stated in the doc.

[brianlovin]

getInitialProps can be used still (legacy), but I believe it's preferred to use getServerSideProps (where the behaviors are loosely the same). As you find places where you would be able to use getStaticProps, that is even better.

Re: using getStaticProps in _app, I did a quick search and found this: #10949