function plt_hide_serial_codes_generator_and_validator_menus() {
//Hide the "Settings → Serial Codes Validator" menu.
remove_submenu_page('options-general.php', 'sngmbh-serialcodes-validator');
//Hide the "Serial Codes Validator" menu.
remove_menu_page('sngmbh-serialcodes-validator');
}
add_action('admin_menu', 'plt_hide_serial_codes_generator_and_validator_menus', 11);