Fatal error: Uncaught Error: Interface 'Zend_Feed_Pubsubhubbub_CallbackInterface' not found in C:\MANTUM\xampp2\htdocs\MNT\ventasvariables2\libreria\Zend\Feed\Pubsubhubbub\CallbackAbstract.php:40 Stack trace: #0 {main} thrown in C:\MANTUM\xampp2\htdocs\MNT\ventasvariables2\libreria\Zend\Feed\Pubsubhubbub\CallbackAbstract.php on line 40