* The deprecated `--service-account-private-key-file` flag has been removed from the cloud-controller-manager. The flag is still present and supported in the kube-controller-manager. ([#65182](https://github.com/kubernetes/kubernetes/pull/65182), [@liggitt](https://github.com/liggitt))

- kubeadm commands now print warnings if input YAML documents contain unknown or duplicate fields.
- kubeadm now properly recognizes Docker 18.09.0 and newer, but still treats 18.06 as the default supported version.
- kubeadm now automatically sets the `--pod-infra-container-image` flag when starting the kubelet.

### SIG IBM Cloud

 - All StorageClass parameters for volume provisioning are supported.
 - All features supported with PersistentVolumeClaims are supported, such as storage capacity tracking, snapshots and restore, and volume resizing.

### Immutable Secrets and ConfigMaps (beta)

### Windows support improved

`kubectl alpha debug` graduates from alpha to beta in 1.20, becoming `kubectl debug`.
`kubectl debug` provides support for common debugging workflows directly from kubectl. Troubleshooting scenarios supported in this release of `kubectl` include:
Troubleshoot workloads that crash on startup by creating a copy of the pod that uses a different container image or command.

- Fixed a bug in the CSI metrics that does not return not supported error when a CSI driver does not support metrics. ([#79851](https://github.com/kubernetes/kubernetes/pull/79851), [@jparklab](https://github.com/jparklab))

feature gate is enabled, user should not upgrade to Kubernetes v1.22. vSphere CSI Driver does not support Kubernetes v1.22 yet because it uses v1beta1 CRD APIs. Support for v1.22 will be added at a later release. Check the following document for supported Kubernetes releases for a given [vSphere CSI Driver version](https://vsphere-csi-driver.sigs.k8s.io/compatiblity_matrix.html#compatibility-matrix-for-vsphere-csi-driver).

### Workloads that saturate nodes with pods may see pods that...

All StorageClass parameters for volume provisioning and all features supported with PersistentVolumeClaims are supported.

### Skip Volume Ownership change graduates to GA

The feature to configure volume permission and ownership change policy for Pods moved to GA in 1.23.

* K8s 1.5 keeps container-vm as the default node image on GCE for backwards compatibility reasons. Please beware that container-vm is officially deprecated (supported with security patches only) and you should replace it with GCI if at all possible. You can review the migration guide here for more detail: https://cloud.google.com/container-engine/docs/node-image-migration ([#36822](https://github.com/kubernet...

## Major Themes

### Dockershim Removed from kubelet

After its deprecation in v1.20, the dockershim component has been removed from the kubelet.
From v1.24 onwards, you will need to either use one of the other [supported runtimes](https://kubernetes.io/docs/setup/production-environment/container-runtimes/) (such as containerd or CRI-O)
or use cri-dockerd if you are relying on Docker Engine as your container runtime.