We recently spent some time tracking down a bug which turned out to be out of date SmartObject methods in our InfoPath form. We had edited our Smartbox methods to add extra service broker calls, for example to save the SmartObject we call the ‘GetCurrentUser’ and ‘GetCurrentDate’ service methods to store the ModifiedBy and ModifiedDate values, then we call the ‘Save’ service method.
Now… if the SmartObject method is integrated with InfoPath and you change the structure of your SmartObject, the service methods are no longer being updated. This means that if you add new fields they won’t appear in the Save method until you edit the SmartObject, delete the call to the Save service method, re-add it, redeploy the SmartObject and then refresh the form.
Just something to keep in mind.