/**
 * Filter if an ipn request is valid or not.
 *
 * @since 1.8.6.3
 *
 * @param bool           $r  true or false if the request is valid
 * @param array|WP_Error $fp remote post object from request to PayPal
 */
$r = apply_filters( 'pmpro_ipn_validate', $r, $fp );