- Added `--output plaintext-openapiv2` argument to kubectl explain to use old openapiv2 `explain` implementation. ([#115480](https://github.com/kubernetes/kubernetes/pull/115480), [@alexzielenski](https://github.com/alexzielenski))

- Windows Kubeproxy will use the update load balancer API for load balancer updates, instead of the previous delete and create APIs.

- `kubeadm.k8s.io/v1beta2` has been deprecated and will be removed in a future release, possibly in 3 releases (one year). You should start using `kubeadm.k8s.io/v1beta3` for new clusters. To migrate your old configuration files on disk you can use the `kubeadm config migrate` command. ([#107013](https://github.com/kubernetes/kubernetes/pull/107013), [@pacoxu](https://github.com/pacoxu))

configure the container runtime to use the "systemd" driver. Documentation on this topic can be found here: https://kubernetes.io/docs/setup/production-environment/container-runtimes/. When upgrading existing clusters / nodes using "kubeadm upgrade" the old cgroupDriver value is preserved, but in 1.22 this change will also apply to "upgrade". For more information on migrating to the "systemd" driver or remaining on the "cgroupfs" driver see: https://kubernetes.io/docs/tasks/administer-cluster/kubeadm/...

- Fix the bug PIP's DNS is deleted if no DNS label service annotation isn't set. ([#87311](https://github.com/kubernetes/kubernetes/pull/87311), [@nilo19](https://github.com/nilo19)) [SIG Cloud Provider]
- Fix: set nil cache entry based on old cache ([#87592](https://github.com/kubernetes/kubernetes/pull/87592), [@aramase](https://github.com/aramase)) [SIG Cloud Provider]

For stable features, the `kubectl` tool follows the Kubernetes [version skew policy](https://kubernetes.io/releases/version-skew-policy/);
however, kubectl v1.21 and older do not support the new API for ephemeral containers.

## Changelog since v1.12.4

### Other notable changes

* kubectl: fixed an issue with "too old resource version" errors continuously appearing when calling `kubectl delete` ([#72825](https://github.com/kubernetes/kubernetes/pull/72825), [@liggitt](https://github.com/liggitt))

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### Bug or Regression

- Ensure daemonset controller to count old unhealthy pods towards max unavailable budget ([#127774](https://github.com/kubernetes/kubernetes/pull/127774), [@ncdc](https://github.com/ncdc)) [SIG Apps]

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