graduated the kubeadm specific feature gate `UnversionedKubeletConfigMap` to GA and locked it to `true` by default. The 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`...

- The feature gate was mentioned as `csiMigrationRBD` where it should have been `CSIMigrationRBD` to be in parity with other migration plugins. This release correct the same and keep it as `CSIMigrationRBD`.

- kubeadm now includes the ability to specify certificate encryption and decryption keys for the upload and download certificate phases as part of the new v1beta2 kubeadm config format. ([#77012](https://github.com/kubernetes/kubernetes/pull/77012), [@rosti](https://github.com/rosti))

  * You can find out what taints you have in place on a node while you are still running Kubernetes 1.5 by doing `kubectl describe node <node name>`; the `Taints` section will show the taints you have in place. To see the taints that were created under 1.5 when you are running 1.6, do `kubectl get node <node name> -o yaml` and look for the...

Kubeadm: Expose the `kubeadm join` workflow as phases

- If `kubeadm reset` finds no etcd member ID for the peer it removes during the `remove-etcd-member` phase, it continues immediately to other phases, instead of retrying the phase for up to 3 minutes before continuing. ([#117916](https://github.com/kubernetes/kubernetes/pull/117916), [@dlipovetsky](https://github.com/dlipovetsky)) [SIG Cluster Lifecycle]

  - A server-side apply request that makes unrelated changes to an object which has duplicate items in a keyed list no longer fails, and leaves the existing duplicate items as-is.

* Azure: Container permissions for provisioned volumes have changed to private. If you have existing Azure volumes that were created by Kubernetes v1.6.0-v1.6.5, you should change the permissions on them manually. ([#47605](https://github.com/kubernetes/kubernetes/pull/47605), [@brendandburns](https://github.com/brendandburns))