Warning: Unsupported declare 'strict_types' in C:\Apache24\htdocs\drupal\vendor\guzzlehttp\promises\src\AggregateException.php on line 3

Fatal error: Class 'GuzzleHttp\Promise\RejectionException' not found in C:\Apache24\htdocs\drupal\vendor\guzzlehttp\promises\src\AggregateException.php on line 11