Run phpunit in version 7 for testing SuiteCRM

I have a bunch of unittests for SuiteCRM that run in phpunit. We have been using for unknown reasons version 5.7.20 (quite old, I know).
I tried using a newer version but I get a backend error from phpunit which I don’t quite understand where it origins. If I run vanialla unittests the version works, just the one that make use of the SuiteCRM beans break.

TypeError: Argument 1 passed to PHPUnit\Framework\TestCase::registerMockObjectsFromTestArguments() must be of the type array, null given

Is there a way to use newer versions of phpunit with SuiteCRM?

Have you checked the Matrix Compatibility?