1. In section 8.4.1, "The Prefer Header", replace: "The client MAY specify a Prefer header on Data Modification Request or Action Request." with: "The client MAY specify a Prefer header value of "return-content" or "return-no-content" on POST, PUT, or PATCH Data Modification Request other than to a named stream property, or to an Action Request. Specifying a value of "return-content" or "return-no-content" in a GET or DELETE request, or any request to a named stream property, SHOULD return a 4xx Client Error. A Prefer header value of "return-content" or "return-no-content" MAY be specified on an individual Data Modification or Action request within a batch, subject to the same restrictions, but SHOULD return a 4xx Client Error if specified on the batch request itself." 2. Add the following to the end of section 10.3.6.2, "Editing a Media Entity Stream": "If the request to edit a Media Entity Stream returns a non-empty response body, the response body MUST contain the updated Media Entity."