code: public void useOldRESTServiceWithNewClientAndXPath() throws Exception {
          List<Object> providers = createJAXRSProviders();
  
          String address = "http://localhost:" + port + "/examples/direct/rest/customerservice";
          WebClient client = WebClient.create(address, providers);
          
          // The outgoing new Customer data needs to be transformed for 
          // the old service to understand it and the response from the old service
          // needs to be transformed for this new client to understand it.
          ClientConfiguration config = WebClient.getConfig(client);
          addTransformInterceptors(config.getInInterceptors(),
                                   config.getOutInterceptors(),
                                   true);
          
          
          System.out.println("Consuming old RESTful CustomerService with new client and XPath");
  
          customer.v2.Customer customer = createNewCustomer("Smith New to Old REST, XPath");
          client.path("customer");
          client.type("application/xml");
          client.put(customer);
          
          XMLSource source = 
              client.query("name", "Smith New to Old REST, XPath").get(XMLSource.class);
          customer.v2.Customer xmlCustomer =
              source.getNode("/ns:customer", 
                             Collections.singletonMap("ns", "http://customer/v2"), 
                             customer.v2.Customer.class);
          printNewCustomerDetails(xmlCustomer);
      }
docs: New REST client uses old REST service