Pro WCF: Practical Microsoft SOA Implementation

Best Practices for Versioning

Versioning, in the context of data contracts, is all about schema validation because the entity that is consumed and used at the end of the schema itself. It is the changes to this schema you need to version. Versioning for data contracts can be divided into two groups—one that requires schema validation and a second that does not. The first group where schema validation is required is quite rare in today's enterprise environment, and many systems can handle the fact that certain elements are extra and not defined in a schema.

With Schema Validation

Data contracts should be considered immutable when schema validation is required "both ways" (that is, new to old, and vice versa). You should create a new data contract ...