ServerChan notifications

Response compatibility

Starting with 1.9.1, a ServerChan notification is successful only when the endpoint returns HTTP 200 and a JSON response containing the numeric field code with value 0, for example:

{"code": 0, "message": ""}

A nonzero code, missing/null code, empty or malformed response, HTTP error or network failure is reported as a notification failure. HTTP 200 alone, or errcode: 0 without code: 0, is not success. A configured compatible endpoint must implement this same response contract; this does not expand the existing endpoint policy.