([#122276](https://github.com/kubernetes/kubernetes/pull/122276), [@pohly](https://github.com/pohly))
- Added a CBOR implementation of `runtime.Serializer`. Until CBOR graduates to Alpha, API servers will refuse to start if configured with CBOR support. ([#122881](https://github.com/kubernetes/kubernetes/pull/122881), [@benluddy](https://github.com/benluddy))

- client-go

*   Refactor kube-scheduler configuration ([#52428](https://github.com/kubernetes/kubernetes/pull/52428))
    *   The kube-scheduler command now supports a --config flag which is the location of a file containing a serialized scheduler configuration. Most other kube-scheduler flags are now deprecated. ([#52562](https://github.com/kubernetes/kubernetes/pull/52562),[ @ironcladlou](https://github.com/ironcladlou))

- Restartable init containers resource in pod autoscaler are now calculated. ([#120001](https://github.com/kubernetes/kubernetes/pull/120001), [@qingwave](https://github.com/qingwave))
- Sidecar termination is now serialized and each sidecar container will receive a `SIGTERM` after all main containers and later starting sidecar containers have terminated. ([#120620](https://github.com/kubernetes/kubernetes/pull/120620), [@tzneal](https://github.com/tzneal))

- The cloud config for Azure cloud provider can now be initialized from Kubernetes secret azure-cloud-provider in kube-system namespace
    - the secret is a serialized version of `azure.json` file with key cloud-config. And the secret name is azure-cloud-provider.

  // Defaulted to nil.
  // +optional
  optional bool immutable = 5;

  // Data contains the secret data. Each key must consist of alphanumeric
  // characters, '-', '_' or '.'. The serialized form of the secret data is a
  // base64 encoded string, representing the arbitrary (possibly non-string)
  // data value here. Described in https://tools.ietf.org/html/rfc4648#section-4
  // +optional

- Fixed a bug in the TopologyManager. Previously, the TopologyManager would only guarantee alignment if container creation was serialized in some way. Alignment is now guaranteed under all scenarios of container creation. ([#87759](https://github.com/kubernetes/kubernetes/pull/87759), [@klueska](https://github.com/klueska)) [SIG Node]

* if kube-apiserver is started with `--storage-backend=etcd2`, the media type `application/json` is used. ([#43122](https://github.com/kubernetes/kubernetes/pull/43122), [@liggitt](https://github.com/liggitt))
* API fields that previously serialized null arrays as `null` and empty arrays as `[]` no longer distinguish between those values and always output `[]` when serializing to JSON. ([#43422](https://github.com/kubernetes/kubernetes/pull/43422), [@liggitt](https://github.com/liggitt))

    <sub-class-of type="application/java-archive"/>
    <glob pattern="*.war"/>
  </mime-type>

  <mime-type type="application/x-tika-unix-dump"/>

  <mime-type type="application/java-serialized-object">
    <glob pattern="*.ser"/>
  </mime-type>

  <mime-type type="application/javascript">
    <alias type="application/x-javascript"/>
    <alias type="text/javascript"/>

## Changelog since v1.8.14

### Action Required