- kube-scheduler dropped support for configuration files with apiVersion `componentconfig/v1alpha1`. Ensure kube-scheduler is configured using command-line flags or a configuration file with apiVersion `kubescheduler.config.k8s.io/v1alpha1` before upgrading to 1.13.
- kubectl

- Kubeadm: deprecate self-hosting support. The experimental command "kubeadm alpha self-hosting" is now deprecated and will be removed in a future release. ([#95125](https://github.com/kubernetes/kubernetes/pull/95125), [@neolit123](https://github.com/neolit123)) [SIG Cluster Lifecycle]

- Kubeadm: deprecated command "alpha selfhosting pivot" is now removed. ([#97627](https://github.com/kubernetes/kubernetes/pull/97627), [@knight42](https://github.com/knight42))

- Kubeadm: remove the deprecated command `kubeadm config view`. A replacement for this command is `kubectl get cm -n kube-system kubeadm-config -o=jsonpath="{.data.ClusterConfiguration}"` ([#102071](https://github.com/kubernetes/kubernetes/pull/102071), [@neolit123](https://github.com/neolit123))

how we can support developers with tooling built on top of `kubectl exec`. The addition of the `kubectl debug` [command](https://github.com/kubernetes/enhancements/blob/master/keps/sig-cli/1441-kubectl-debug/README.md) (it is alpha but your feedback is more than welcome), allows developers to easily debug their Pods inside the cluster. We think this addition is invaluable.  This command allows one to create a temporary container which runs next to the Pod one is trying to examine, but also attaches...

    * clusters. When that var is set to true, the command line flag enabling kubelet
    * client certificate rotation will be added to the kubelet command line.

* kubeadm: a new command `kubeadm upgrade node` is introduced for upgrading nodes (both secondary control-plane nodes and worker nodes)  ([#78408](https://github.com/kubernetes/kubernetes/pull/78408), [@fabriziopandini](https://github.com/fabriziopandini))
    * The command `kubeadm upgrade node config` is now deprecated; use `kubeadm upgrade node` instead.

- If a bad flag is supplied to a kubectl command, only a tip to run `--help` is printed, instead of the usage menu.  Usage menu is printed upon running `kubectl command --help`. ([#82423](https://github.com/kubernetes/kubernetes/pull/82423), [@sallyom](https://github.com/sallyom))

  spec with the `--serviceaccount` flag.

- `kubectl proxy` now correctly handles the `exec`, `attach`, and
  `portforward` commands.  You must pass `--disable-filter` to the command to allow these commands.

- Added `cronjobs.batch` to "all", so that `kubectl get all` returns them.

- Added flag `--include-uninitialized` to `kubectl annotate`, `apply`, `edit-last-applied`,

* `kubectl wait` is a new command that allows waiting for one or more resources to be deleted or to reach a specific condition. It adds a `kubectl wait --for=[delete|condition=condition-name] resource/string` command. ([#64034](https://github.com/kubernetes/kubernetes/pull/64034), [@deads2k](https://github.com/deads2k))