PHP-ERROR >><br />
<b>Fatal error</b>:  Uncaught Error: Class 'Drupal\Core\Installer\InstallerKernel' not found in /opt/drupal/web/core/includes/errors.inc:311
Stack trace:
#0 /opt/drupal/web/core/includes/errors.inc(125): _drupal_get_error_level()
#1 /opt/drupal/web/core/includes/bootstrap.inc(638): error_displayable()
#2 /opt/drupal/web/core/includes/bootstrap.inc(622): _drupal_exception_handler_additional(Object(Error), Object(Error))
#3 [internal function]: _drupal_exception_handler(Object(Error))
#4 {main}
  thrown in <b>/opt/drupal/web/core/includes/errors.inc</b> on line <b>311</b><br />