Version Discovery

Requiring an explicit service version helps ensure existing clients don’t break, but we also need a way to advertise which service versions are currently supported and which versions are deprecated.

To facilitate this need, services should respond with the api-supported-versions and api-deprecated-versions, which are multi-value HTTP headers that indicate the supported and deprecated API versions, respectively. A deprecated version is still implemented, but is expected to be permanently removed in six months or more. When a version is no longer supported, it should stop being advertised.

Reporting API versions is disabled by default. Service authors can enable this behavior by setting the ApiVersioningOptions.ReportApiVersions to true.