The `DeclarativeValidationTakeover` feature gate remains disabled by default.  While disabled, validation errors produced by hand written validation are always return to the caller.  To switch to declarative validation is primary source of errors for migrated fields, enable this feature gate. ([#130728](https://github.com/kubernetes/kubernetes/pull/130728), [@jpbet...

  can also be scheduled to nodes with `GA` labels. ([#118923](https://github.com/kubernetes/kubernetes/pull/118923), [@AxeZhan](https://github.com/AxeZhan))
- Updated the generic apiserver library to produce an error if a new API server is configured with support for a data format other than JSON, YAML, or Protobuf. ([#121325](https://github.com/kubernetes/kubernetes/pull/121325), [@benluddy](https://github.com/benluddy)) [SIG API Machinery]

- Graduated the `LegacyServiceAccountTokenTracking` feature gate to Beta. The usage of auto-generated secret-based service account token now produces warnings by default, and relevant Secrets are labeled with a last-used timestamp (label key `kubernetes.io/legacy-token-last-used`). ([#114523](https://github.com/kubernetes/kubernetes/pull/114523), [@zshihang](https://github.com/zshihang)) [SIG...

- X.509 client certificate authentication to the kube-apiserver now produces credential IDs (derived from the certificate's signature) , for use in audit logging. ([#125634](https://github.com/kubernetes/kubernetes/pull/125634), [@ahmedtd](https://github.com/ahmedtd)) [SIG API Machinery, Auth and Testing]

- Allow CSI drivers to just run offline expansion tests. ([#102665](https://github.com/kubernetes/kubernetes/pull/102665), [@gnufied](https://github.com/gnufied))
- Changed buildmode of non static Kubernetes binaries to produce position independent executables (PIE). ([#102323](https://github.com/kubernetes/kubernetes/pull/102323), [@saschagrunert](https://github.com/saschagrunert))

* Transition service account controller clients to TokenRequest API ([#72179](https://github.com/kubernetes/kubernetes/pull/72179), [@WanLinghao](https://github.com/WanLinghao))
* kubeadm: reimplemented IPVS Proxy check that produced confusing warning message. ([#75036](https://github.com/kubernetes/kubernetes/pull/75036), [@bart0sh](https://github.com/bart0sh))

* Add /bin/tee symlink to bazel build for busybox, so that CI builds have /bin/tee ([#55417](https://github.com/kubernetes/kubernetes/pull/55417), [@justinsb](https://github.com/justinsb))
* Reduce log noise produced by prometheus-to-sd, by bumping it to version 0.2.2. ([#54635](https://github.com/kubernetes/kubernetes/pull/54635), [@loburm](https://github.com/loburm))

## Changelog since v1.19.0

## What's New (Major Themes)

### Dockershim deprecation

Docker as an underlying runtime is being deprecated. Docker-produced images will continue to work in your cluster with all runtimes, as they always have.