Introducing new Enum value doesn't result in default value in client

We have a client generated using protoc with the Typescript option included and are then making requests using grpc-web.

We recently introduced a new value to an enum, and as we are following the proto guidelines of have a default value assigned to 0 for the first value of the enum, we expected the the client to default to this value until it was updated and made aware of the new enum value.

This does not seem to have happened, instead the int value of the enum is present.

Is there a setting that can be applied so that the default enum value is used in the situation the client is unaware of the enum value?

Start by reproducing the behavior with a protoc-generated TypeScript client and grpc-web after adding an enum value that the client does not know about. Check how the generated client represents that value and whether an existing setting or test covers unknown enums; done means the default enum value is used, or the limitation is documented clearly.

Written by the indexing model from the issue text.