LG Leon kaljeno zaščitno steklo

<?php

add_filter( 'woocommerce_order_number', function ( $order_id, $order ) {
    $prefix = 'MKS-';
	$suffix = '';
    // $suffix = '-' . date(Y); 
    // You can use either one of $order->id (or) $order_id
    // Both will work
    return $prefix . $order->id . $suffix;
}, 1, 2);