A pilot image does not cover every dependency

A fictional team updates a source image and successfully launches one administrator session. The planned rollout includes standard users with printers, a line-of-business application, profile containers and an externally stored application configuration. A second test reports a changed user-data format, and the team has not verified whether the old image can read it. A supplier says an image snapshot makes every later change reversible, so no further test is necessary. The exercise is limited to written planning and supplied results. It asks which evidence is needed before broad promotion and how rollback should account for external state, without issuing an image update, restoring a snapshot or changing the live catalog.