Fatal error: Uncaught Error: Class "PKP\filter\CompositeFilter" not found in C:\xampp\htdocs\ojs\lib\pkp\classes\filter\GenericMultiplexerFilter.php:23 Stack trace: #0 {main} thrown in C:\xampp\htdocs\ojs\lib\pkp\classes\filter\GenericMultiplexerFilter.php on line 23