I have a very old install that began with 6 and is now at 8. I'm trying to get it updated to 9 but have gotten stuck with getting the upgrade_status module to work. After it was installed via composer, I get this error when navigating to the report:
The website encountered an unexpected error. Please try again later. InvalidArgumentException: Class "\Drupal\upgrade_status\Form\UpgradeStatusForm" does not exist. in Drupal\Core\DependencyInjection\ClassResolver->getInstanceFromDefinition() (line 24 of core/lib/Drupal/Core/DependencyInjection/ClassResolver.php).
I then tried to manually install it (very hacky) in the
/modules directory to no effect.
I'm not sure if my install of Drupal is hopelessly broken and stuck at 8. I appreciate any suggestions or additional info that will help me troubleshoot it.