Question: In a 5G system, when a GBA BSF sends a PATCH request to modify a subscription related to changes in GBA subscriber data, what HTTP status code is returned by the HSS if all changes are accepted, but no content is returned in the response body?
Option 1: 200 OK with an empty response body
Option 2: 204 No Content
Option 3: 201 Created with a Location header pointing to the updated resource
Option 4: 202 Accepted indicating processing is pending
Explanation: According to the 5G system's HSS services specification, when all changes in a subscription modification request (related to GBA subscriber data) are successfully accepted and no additional content needs to be returned, the HSS responds with an HTTP status code 204 No Content. This indicates successful processing without providing a response body, aligning with the principles of HTTP/1.1 for such scenarios where no content is being carried in the response message.