Pluto
A cli tool to help discover deprecated apiVersions in Kubernetes
...However, it can be difficult to find all the places where you might have used a version that will be deprecated in your next upgrade. You might think, "I'll just ask the api-server to tell me!", but this is fraught with danger. If you ask the API-server to give you deployments.v1.apps, and the deployment was deployed as deployments.v1beta1.extensions, the API-server will quite happily convert the API version and return a manifest with apps/v1. This is fairly well outlined in the discussion of this issue.