- The list of validated docker versions remain unchanged at 1.11.1, 1.12.1, 1.13.1, 17.03, 17.06, 17.09, 18.06 since Kubernetes 1.12. ([#68495](https://github.com/kubernetes/kubernetes/pull/68495))
- The default Go version was updated to 1.11.2. ([#70665](https://github.com/kubernetes/kubernetes/pull/70665))
- The minimum supported Go version was updated to 1.11.2 ([#69386](https://github.com/kubernetes/kubernetes/pull/69386))

## Action Required

- etcd2 as a backend is deprecated and support will be removed in Kubernetes 1.13.

    - [Am I vulnerable?](#am-i-vulnerable)
      - [Affected Versions](#affected-versions)
    - [How do I mitigate this vulnerability?](#how-do-i-mitigate-this-vulnerability)
      - [Fixed Versions](#fixed-versions)
    - [Detection](#detection)
      - [Additional Details](#additional-details)
      - [Acknowledgements](#acknowledgements)

- `kubectl api-resources` now prints the API version (as 'API group/version', same as output of `kubectl api-versions`). The column APIGROUP is now APIVERSION ([#95253](https://github.com/kubernetes/kubernetes/pull/95253), [@sallyom](https://github.com/sallyom)) [SIG CLI]

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.

- `kubeadm`: will now allow deploying a kubelet that is 3 versions older than the version of `kubeadm` (N-3). This aligns with the recent change made by SIG Architecture that extends the support skew between the control plane and kubelets. Tolerate this new kubelet skew for the commands `init`, `join` and `upgrade`. Note that if the `kubeadm` user applies a control plane version that is older than the `kubeadm` version (N-1 maximum) then the skew between the kubelet and control plane would...

- Kubeadm: upgrade supports fallback to the nearest known etcd version if an unknown k8s version is passed ([#88373](https://github.com/kubernetes/kubernetes/pull/88373), [@SataQiu](https://github.com/SataQiu)) [SIG Cluster Lifecycle]

    - `kubectl create clusterrolebinding anonymous-access-review --clusterrole=system:basic-user --group=system:unauthenticated`
  - The deprecated --storage-versions flag has been removed. The storage versions will always be the default value built-in the kube-apiserver binary. ([#67678](https://github.com/kubernetes/kubernetes/pull/67678), [@caesarxuchao](https://github.com/caesarxuchao))

- Kubectl version changed to write a warning message to stderr if the client and server version difference exceeds the supported version skew of +/-1 minor version. ([#98250](https://github.com/kubernetes/kubernetes/pull/98250), [@brianpursley](https://github.com/brianpursley)) [SIG CLI]

- OpenAPI V2 will no longer publish aggregated API server OpenAPI for group versions that do not match the APIService specified group version. ([#123570](https://github.com/kubernetes/kubernetes/pull/123570), [@Jefftree](https://github.com/Jefftree))