High level description is react gets upgraded (to react 18, the currently supported version-- we are currently on 16.14), then all of the "@material-ui" packages get updated to the abbreviated "@mui" packages, with additional new MUI 5 "emotion packages".
At this point, you can either ctrl + f all of the above mentioned breaking changes and fix them first, or you can brute force things by running the application and fixing all of the runtime errors. Alternatively, there's a number of tools out there that can try to do this for you that should be pretty comprehensive, since people started working through the transition in 2021. https://mui.com/blog/mui-core-v5/
MUI 5 is the current stable version; MUI 6 is still under development, so this will completely catch us up. https://mui.com/versions/
Luckily provided are very extensive upgrade notes, with detailed instructions including all breaking changes https://mui.com/material-ui/migration/migration-v4/
High level description is react gets upgraded (to react 18, the currently supported version-- we are currently on 16.14), then all of the "@material-ui" packages get updated to the abbreviated "@mui" packages, with additional new MUI 5 "emotion packages".
At this point, you can either ctrl + f all of the above mentioned breaking changes and fix them first, or you can brute force things by running the application and fixing all of the runtime errors. Alternatively, there's a number of tools out there that can try to do this for you that should be pretty comprehensive, since people started working through the transition in 2021. https://mui.com/blog/mui-core-v5/