* kubeadm: Support for `.AuthorizationModes` in the kubeadm v1alpha2 API has been removed. Instead, you can use the `.APIServerExtraArgs`...

  - Scheduler Extenders can now be configured in the v1alpha2 component config ([#88768](https://github.com/kubernetes/kubernetes/pull/88768), [@damemi](https://github.com/damemi)) [SIG Release, Scheduling and Testing]

If a container runtime does not support the `v1` API, Kubernetes will fall back to the `v1alpha2` implementation.
There is no intermediate action required by end-users, because `v1` and `v1alpha2` do not differ in their implementation.
It is likely that `v1alpha2` will be removed in one of the future Kubernetes releases to be able to develop `v1`.

### Structured logging graduate to Beta

  to kubelet config ([#112136](https://github.com/kubernetes/kubernetes/pull/112136), [@pacoxu](https://github.com/pacoxu))
- `resource.k8s.io/v1alpha1` was replaced with `resource.k8s.io/v1alpha2`. Before
  upgrading a cluster, all objects in resource.k8s.io/v1alpha1 (ResourceClaim, ResourceClaimTemplate,
  ResourceClass, PodScheduling) must be deleted. The changes are internal, so

  * [stable] [cri-o](https://github.com/kubernetes-incubator/cri-o): cri-o v1.10 updated CRI version to v1alpha2 and made several bug and stability fixes. [@mrunalp]

- The `NodeConfiguration` kind in the kubeadm v1alpha2 API has been renamed `JoinConfiguration` in v1alpha3 ([#65951](https://github.com/kubernetes/kubernetes/pull/65951), [@luxas](https://github.com/luxas)) Courtesy of SIG Cluster Lifecycle

- Kubeadm: removed the deprecated `output.kubeadm.k8s.io/v1alpha2` API for structured output. Please use v1alpha3 instead. ([#124496](https://github.com/kubernetes/kubernetes/pull/124496), [@carlory](https://github.com/carlory))

- `v1beta1` Scheduler `Extender` encoding is case-sensitive (`v1alpha1`/`v1alpha2` was case-insensitive), its `httpTimeout` field uses duration encoding (for example, one second is specified as `"1s"`), and the `enableHttps` field in `v1alpha1`/`v1alpha2` was renamed to `enableHTTPS`. ([#91625](https://github.com/kubernetes/kubernetes/pull/91625), [@pancernik](https://github.com/pancernik)) [SIG Scheduling]...

* [action required] kubeadm: The `v1alpha2` config API has been removed. ([#69055](https://github.com/kubernetes/kubernetes/pull/69055), [@fabriziopandini](https://github.com/fabriziopandini))
    * Please convert your `v1alpha2` configuration files to `v1alpha3` using the
    * `kubeadm config migrate` command of kubeadm v1.12.x

### Other notable changes

- Coordination.v1alpha1 API is dropped and replaced with coordination.v1alpha2. Old coordination.v1alpha1 types must be deleted before upgrade ([#127857](https://github.com/kubernetes/kubernetes/pull/127857), [@Jefftree](https://github.com/Jefftree)) [SIG API Machinery, Etcd, Scheduling and Testing]