SOA Patterns > Service Governance Patterns > Compatible Change
Compatible Change (Orchard, Riley)
How can a service contract be modified without impacting consumers?
Changing an already-published service contract can impact and invalidate existing consumer programs.
Some changes to the service contract can be backwardscompatible, thereby avoiding negative consumer impacts.
Service contract changes can be accommodated via extension or by the loosening of existing constraints or by applying Concurrent Contracts.
Compatible changes still introduce versioning governance effort, and the technique of loosening constraints can lead to vague contract designs.
The existing capability is not renamed. Instead, a new capability with a new name is added alongside the original capability, thereby preserving compatibility with both Consumers A and B.