Upgrade mostly successful. I ran into some issues with a custom template for an Express Form, but changed how that rendered. Fixed that issue.

My last issue is with a page that I do not see a form on, but still giving me the error:

Class Concrete\Core\Express\Form\StandardViewRenderer does not exist.

Its coming from concrete/vendor/illuminate/container/Container.php and the line in question is:
$reflector = new ReflectionClass($concrete);

Lost at this point, it seems like an Express Form issue.