- 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

### SIG Cluster Lifecycle

- Alpha implementation of Kubectl Command Headers: SIG CLI KEP 859 enabled when KUBECTL_COMMAND_HEADERS environment variable set on the client command line.
  - To enable: export KUBECTL_COMMAND_HEADERS=1; kubectl ... ([#98952](https://github.com/kubernetes/kubernetes/pull/98952), [@seans3](https://github.com/seans3)) [SIG API Machinery and CLI]

*   Fixed an issue where `kubectl set` commands occasionally encountered conversion errors for ReplicaSet and DaemonSet objects ([#53158](https://github.com/kubernetes/kubernetes/pull/53158),[ @liggitt](https://github.com/liggitt))

### **Cluster Lifecycle**

#### **API Server**

tes/pull/58171), [@verult](https://github.com/verult))

* Default values differ between the Kubelet's componentconfig (config file) API and the Kubelet's command line. Be sure to review the default values when migrating to using a config file. For example, the authz mode is set to "AlwaysAllow" if you rely on the command line, but defaults to the more secure "Webhook" mode if you load config from a file. ([#59666](https://github.com/kubernetes/kubernetes/pull/59666), [@mtaufen](https...

- Kubeadm: fix panic in the command "kubeadm certs check-expiration" when "/etc/kubernetes/pki" exists but cannot be read. ([#124124](https://github.com/kubernetes/kubernetes/pull/124124), [@carlory](https://github.com/carlory)) [SIG Cluster Lifecycle]

  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`,

  - kubeadm now handles air-gapped environments by using the local client version as a fallback.
  - Some kubeadm commands are now allowed to work in a completely offline mode.
- Certificate handling improvements:
  - Renew certs as part of upgrade.
  - New `kubeadm alpha phase certs renew` command for renewing certificates.
  - Certificates created with kubeadm now have improved uniqueness of Distinguished Name fields.

- The helping message of commands which have sub-commands is now clearer and more instructive. It will show the full command instead of `kubectl <command> --help ...`
  

- 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))