Avro schema : is adding an enum value to existing schema backward compatible?

Question

I have an enum field for status in my Avro schema in which the possible statuses currently are

PENDING
APPROVED
REJECTED

I want to add one mor

Answer 1

No, it is not. Here's why: If you are using this new schema to, let's say, emit events to Kafka, then all clients will try to deserialize the value. When event with new type will appear, there would be 2 cases:

1. clients with new schema will deserialize successfully
2. clients with the old schema will fail to deserialize, because they don't have such value in their enum

So, no, this is not backward compatible.

Answer 2

I don't think it is, but you are welcome to use the Schema Registry API to verify compatbility

https://docs.confluent.io/current/schema-registry/develop/api.html#id1