204
204 is an HTTP status code used to indicate that a request has succeeded, but that the client doesn’t need to navigate away from its current page.
Micropub
The Micropub specification recommends using either a 200 or 204 status code when responding to update or delete action (with 201 used if the update resulted in the post’s URL changing):
...the server MUST respond with 200 or 204, depending on whether the response body has content. No body is required in the response, but the response MAY contain a JSON object describing the changes that were made.
If you want to provide some additional context about the changes made, use 200. Otherwise, use 204.