The `flowcontrol.apiserver.k8s.io/v1beta3` APIs are deprecated and will no longer be served in v1.32. All existing objects are available via the `v1` APIs. Transition clients and manifests to use the `v1` APIs before upgrading to `v1.32`. ([#121089](https://github.com/kubernetes/kubernetes/pull/121089), [@tkashem](https://github.com/tkashem))

- Removed deprecated gogo protocol definitions from `k8s.io/kms/apis` in favor of `google.golang.org/protobuf`. ([#132833](https://github.com/kubernetes/kubernetes/pull/132833), [@saschagrunert](https://github.com/saschagrunert)) [SIG API Machinery, Auth and Testing]

## Changelog since v1.21.0

## What's New (Major Themes)

### Removal of several beta Kubernetes APIs

- External facing APIs in plugin registration and device plugin packages are now available under k8s.io/kubelet/pkg/apis/ ([#83551](https://github.com/kubernetes/kubernetes/pull/83551), [@dims](https://github.com/dims))
### Release

* The kube-apiserver discovery APIs (for example, `/apis`) return information about the API groups being served, and can change dynamically.
During server startup, prior to the server reporting healthy (via `/healthz`), not all API groups may be reported.
Wait for the server to report healthy (via `/healthz`) before depending on the information provided by the discovery APIs.

- OpenAPI will no longer duplicate these schemas:
  - `io.k8s.apimachinery.pkg.apis.meta.v1.DeleteOptions_v2`
  - `io.k8s.apimachinery.pkg.apis.meta.v1.ObjectMeta_v2`
  - `io.k8s.apimachinery.pkg.apis.meta.v1.OwnerReference_v2`
  - `io.k8s.apimachinery.pkg.apis.meta.v1.StatusDetails_v2`

[Sig API Machinery]: https://github.com/kubernetes/community/tree/master/sig-api-machinery

### SIG Apps

[SIG Apps][] focuses on the Kubernetes APIs and the external tools that are required to deploy and operate Kubernetes workloads.

- kube-apiserver:

## Changelog since v1.16.3

### Other notable changes

* Fixed issue with addon-resizer using deprecated extensions APIs ([#85793](https://github.com/kubernetes/kubernetes/pull/85793), [@bskiba](https://github.com/bskiba))

  - [1.15 What’s New](#115-what’s-new)
    - [Continuous Improvement](#continuous-improvement)
    - [Extensibility](#extensibility)
  - [Extensibility around core Kubernetes APIs](#extensibility-around-core-kubernetes-apis)
    - [CustomResourceDefinitions Pruning](#customresourcedefinitions-pruning)
    - [CustomResourceDefinition Defaulting](#customresourcedefinition-defaulting)