class ResponseLevel0(JSONResponse):
    media_type = "application/x-level-0"


class ResponseLevel1(JSONResponse):
    media_type = "application/x-level-1"


class ResponseLevel2(JSONResponse):
    media_type = "application/x-level-2"


class ResponseLevel3(JSONResponse):
    media_type = "application/x-level-3"


class ResponseLevel4(JSONResponse):
    media_type = "application/x-level-4"

    - [**Other notable changes**](#other-notable-changes-16)
      - [Admission plugin](#admission-plugin)
      - [API Machinery](#api-machinery-1)
      - [Application autoscaling](#application-autoscaling-1)
      - [Application Deployment](#application-deployment-1)
      - [Cluster Autoscaling](#cluster-autoscaling)
      - [Cloud Provider Enhancement](#cloud-provider-enhancement)

backup.

Also, please note:
- using `application/vnd.kubernetes.protobuf` as the media storage type for 1.6 is default but not required
- the ability to rollback to etcd2 can be preserved by setting the storage media type flag on `kube-apiserver`

  ```
  --storage-media-type application/json
  ```

  to continue to use `application/json` as the storage media type which can be changed to

    <td>GET /swagger.json</td>
    <td>GET /openapi/v2
Accept: application/json</td>
  </tr>
  <tr>
    <td>GET /swagger-2.0.0.pb-v1</td>
    <td>GET /openapi/v2
Accept: application/com.github.proto-openapi.spec.v2@v1.0+protobuf</td>
  </tr>
  <tr>
    <td>GET /swagger-2.0.0.pb-v1.gz</td>
    <td>GET /openapi/v2
Accept: application/com.github.proto-openapi.spec.v2@v1.0+protobuf Accept-Encoding: gzip</td>

- CBOR-encoded watch responses now set the Content-Type header to "application/cbor-seq" instead of the nonconformant "application/cbor". ([#128501](https://github.com/kubernetes/kubernetes/pull/128501), [@benluddy](https://github.com/benluddy)) [SIG API Machinery, Etcd and Testing]

volume plugin ( `kubernetes.io/cephfs`) was removed in this release and the `cephfs` volume type became non-functional. Alternative is to use CephFS CSI driver (https://github.com/ceph/ceph-csi/) in your Kubernetes Cluster. A re-deployment of your application is required to use the new driver if you were using `kubernetes.io/cephfs` volume plugin before upgrading cluster version to 1.31+. ([#124544](https://github.com/kubernetes/kubernetes/pull/124544), [@carlory](https://github.com/carlory)) [SIG Node,...

  * The webhook and log file now output the `v1beta1` event format.

    For more details, see [Advanced audit](https://kubernetes.io/docs/tasks/debug-application-cluster/audit/#advanced-audit).

* The deprecated `ThirdPartyResource` (TPR) API was removed.

- Extended resources backed by DRA feature allowed cluster operator to specify `extendedResourceName` in `DeviceClass`, and application operator to continue using extended resources in pod's requests to request for DRA devices matching the DeviceClass.
  

    * If the serialization type is application/vnd.kubernetes.protobuf, and protobuf marshaling is not implemented for the requested API resource type, a '406 Not Acceptable is returned'.
    * If the serialization type is 'application/json':

- The `client-go` dynamic client sets the header `Content-Type: application/json` by default ([#104327](https://github.com/kubernetes/kubernetes/pull/104327), [@sxllwx](https://github.com/sxllwx))