Kubernetes API upgrade versions are manually transcribed from the [Kubernetes API deprecation guide][1].
The Kubernetes API deprecation guide is updated regularly, so this list may be out of date.
This also contains some flux custom resources which where also manually added from [flux releases][2] as well as [external secrets][3] custom resources.

[1]: https://kubernetes.io/docs/reference/using-api/deprecation-guide/
[2]: https://github.com/fluxcd/flux2/releases
[3]: https://external-secrets.io/latest/api/spec/