Those are warnings and notices, no errors. You can continue using them.

You're probably working on an older project, maybe you follow a tutorial from a few years ago. What composer is saying is that some of the dependencies (open source code) has changed its official name or that newer versions of the dependency removed/renamed/changed some class.

Composer might still successfully install the dependencies. After you complete all setup steps run 'composer test' and see if it executes.

To get rid of some warnings/notices you can do 'composer update', but that could break your project because newer versions of some of the dependencies might have backward compatibility issues.

Please mark the thread as resolved if everything is working fine.