title: Different PHPUnit versions
body: <p>I'm having an issue with my PHPUnit version (currently version 8). </p>
  
  <p>When I try to run a specific test suite, it's giving me an error, which, based on what I've read online, is a result of the test suite being written for version 7. So, it seems like I'll need to get that version to run the suite. Would you happen to know if I'd necessarily have to uninstall v. 8, or is there a way to overwrite v. 8 with v. 7 (or to have both on my system)?</p>