Please follow
this guide to migrate to the latest version v201607. Since you are on version v201601, I would recommend checking for breaking changes in
v201603 and
v201605 as well. Also, please note that these guides contain the list of changes in the SOAP API, irrespective of the client library (Java, Python etc). As an example, in v201607, get() method of
CustomerService was removed. That means, in your Java client library, if you try the following code, you would get a compile time error:
CustomerServiceInterface customerService = adWordsServices.get(session, CustomerServiceInterface.class);
Customer customer = customerService.get()[0];
The following piece of code is the correct way to fetch the customer:
CustomerServiceInterface customerService = adWordsServices.get(session, CustomerServiceInterface.class);
Customer customer = customerService.getCustomers()[0];
Hope this helps. Please feel free to revert in case you have more questions.