You are building a Microsoft Entra ID–integrated app that calls Microsoft Graph and must accept future unknown enumeration members (support evolvable enumerations) on GET operations. Which HTTP request header enables that behavior?

The Prefer header with the value odata.include-annotations="OData.Community.Display.V1.FormattedValue" (or similar OData preference) is used to request that the service include additional information, such as evolvable enumeration members, in the response. This allows the client to handle future unknown enumeration values gracefully without breaking the application. Accept specifies the media types that the client is willing to accept in the response, not how enumeration members are handled. Content-Type indicates the media type of the request body, not a preference for response content. If-Match is used for optimistic concurrency control, ensuring that an update or delete operation only proceeds if the resource's ETag matches the provided value.