Backend & systems·API and interface design
you change the message format and have to make sure the consumers still on the old schema can read the new messages.
Schema evolution
Also calledcontract evolution, Avro compatibility
Managing changes to a serialisation contract so producers and consumers can be deployed independently. Formats like Avro and Protobuf encode the rules — optional fields, reserved tags, never reuse a field number — and a schema registry enforces them. The rules exist because in any rolling deploy the producer and consumer are briefly on different versions.