CRM 2013 WebService Batch Program

Hi,

     We have one batch program written using CRM WebService for CRM 4.0 which sync accounts/contact everyday from other system to CRM system.

Now we need to change CRM Batch program top work with CRM 2013 using same web service. Any idea , whether is that significant change in CRM Web service for version 4.0 to 2013 or its same??

I mean does CrmService.Update/CrmService.Create has any big difference as  far as accepting parameter and execution and any thing else??