sts-status-update-mail-subject

/**
 * Filters the mail subject
 *
 * @since 1.0.7
 *
 * @param 	(string) 	$subject 	 	the subject
 * @param 	(int) 		$post_id		the ticket ID
 * @param 	(array) 	$post_data		the post data
 * @return 	(string) 	$subject 		the subject
 */

Filter the mail subject of the status update mail sent by sts_send_status_update_mail()