Checkmk Werk 12337: REST API: acknowledgement - not found on update is a 400

ID: 12337 Title: REST API: acknowledgement - not found on update is a 400 Component: Core & setup Level: 1 Class: Bug fix Version: 2.1.0i1 When acknowledging a non existing service, a HTTP 404 was about to be triggered, but was not defined for this endpoint. This could lead to an HTTP 500 (Internal Server Error). This has now been fixed to correctly return a HTTP 400 (Bad Request) error, which is defined for this endpoint, brining it in line with the documentation.