Web Service Versioning - Adding Operations to a Service Contract in WCF

Question

In a WCF service, what happens if I add methods as operation contracts after clients (that consume the service) have completed their implementations? Will the existing clients have to modify their implementations even though they do not use the new operation contract methods?

EDIT: Will the clients have to update their proxy even though they don't use the new contracts?

Answer 1

No, new operation contracts in the service will not break the client's interface. You can freely change your interface as long as the method signatures that the client relies on remain unscathed. This means that you can add as many new interface members as you wish.