wcfm-add-shipped-order-status

add_action('init', function () {
    register_post_status('wc-shipped', array(
        'label' => __( 'Shipped', 'woocommerce' ),
        'public' => true,
        'exclude_from_search' => false,
        'show_in_admin_all_list' => true,
        'show_in_admin_status_list' => true,
        'label_count' => _n_noop('Shipped <span class="count">(%s)</span>', 'Shipped <span class="count">(%s)</span>')
    ));
});
add_filter('wc_order_statuses', function ($order_statuses) {
    $new_order_statuses = array();
    foreach ($order_statuses as $key => $status) {
        $new_order_statuses[$key] = $status;
        if ('wc-processing' === $key) {
            $new_order_statuses['wc-shipped'] = __('Shipped', 'woocommerce' );
        }
    }
    return $new_order_statuses;
});
add_filter('wcfm_is_allow_change_main_order_status_on_all_item_shipped', '__return_true');
add_filter('wcfm_main_order_status_on_all_item_shipped', function($status) {
    return 'shipped';
});
add_action( 'before_wcfm_order_status_update', function() {
    global $WCFMmp;
    remove_action( 'before_wcfm_order_status_update', array( $WCFMmp->ajax, 'wcfmmp_vendor_order_status_update' ), 10 );
}, 9);