* rbac.authorization.k8s.io/v1alpha1

    * settings.k8s.io/v1alpha1

    * If you wish to continue using them in v1.8, please enable them explicitly using the `--runtime-config` flag on the apiserver (for example, `--runtime-config="rbac.authorization.k8s.io/v1alpha1,settings.k8s.io/v1alpha1"`)

feature by default. This implies that 1) for new clusters kubeadm will start using the `kube-system/kubelet-config` naming scheme for the kubelet ConfigMap and RBAC rules, instead of the legacy `kubelet-config-x.yy` naming. 2) during upgrade, kubeadm will only write the new scheme ConfigMap and RBAC objects. To disable the feature you can pass `UnversionedKubeletConfigMap: false` in the kubeadm config for new clusters. For upgrade on existing clusters you can also override the behavior by patching the...

- Kubelet config file will be backed up to `/etc/kubernetes/tmp/` folder with `kubeadm-kubelet-config` append with a random suffix as the filename ([#114695](https://github.com/kubernetes/kubernetes/pull/114695), [@chendave](https://github.com/chendave)) [SIG Cluster Lifecycle]

`init` and `join` it is now recommended that you migrate to configure patches via `{Init|Join}Configuration.patches.directory`. For the time being, these flags can be mixed with `--config`, but that might change in the future. On a command line, the last *patches flag takes precedence over previous flags and the value in config. `kubeadm upgrade --patches` will continue to be the only available option, since `upgrade` does not support a configuration file yet. ([#103063](https://github.com/kubernetes...

- KMS: added validation for duplicate kms config name when auto reload is enabled. If you enabled automatic reload of encryption configuration with API server flag `--encryption-provider-config-automatic-reload`, ensure all the KMS provider names (v1 and v2) in the encryption configuration...

kubelet related ConfigMap and RBAC rules are now locked to have a simplified naming `*kubelet-config` instead of the legacy naming `*kubelet-config-x.yy`, where `x.yy` was the version of the control plane. If you have previously used the old naming format with `UnversionedKubeletConfigMap=false`, you must manually copy the config map from `kube-system/kubelet-config-x.yy` to `kube-system/kubelet-config` before upgrading to `v1.25`. ([#110327](https://github.com/kubernetes/kubernetes/pull/110327),...

- Kubeadm: deprecate the "kubeadm alpha kubelet config enable-dynamic" command. To continue using the feature please defer to the guide for "Dynamic Kubelet Configuration" at k8s.io. ([#92881](https://github.com/kubernetes/kubernetes/pull/92881), [@neolit123](https://github.com/neolit123)) [SIG Cluster Lifecycle]

## Changelog since v1.8.14

### Action Required

* ACTION REQUIRED: Kubernetes JSON deserializer is now case-sensitive to restore compatibility with pre-1.8 servers. If your config files contains fields with wrong case, the config files will be now invalid. ([#65410](https://github.com/kubernetes/kubernetes/pull/65410), [@nikhita](https://github.com/nikhita))

### Other notable changes

* kubeadm: remove deprecated kubeadm config print-defaults command ([#71467](https://github.com/kuberne...

- Add flag --lease-max-object-size and metric etcd_lease_object_counts for kube-apiserver to config and observe max objects attached to a single etcd lease. ([#97480](https://github.com/kubernetes/kubernetes/pull/97480), [@lingsamuel](https://github.com/lingsamuel)) [SIG API Machinery, Instrumentation and Scalability]