<Order OrderNumber="1000" OrderVersion="1" ...>
  <Products>
    <Product Code="X58" Price="$5.50" Quantity="3" ... />
    <Product Code="X70" Price="$9.99" Quantity="1" ... />
  </Products>
  <Contacts>
    <Contact ... />
    <Contact ... />
  </Contacts>
</Order>

UPDATE c
SET c.ZipCode = ...
FROM Contact c
    INNER JOIN Order o ON c.OrderId = o.OrderId
WHERE o.Version = 1
  AND ...