- Client-go: Clients can request protobuf and json and correctly negotiate with the server for JSON for CRD objects, allowing all client libraries to request protobuf if it is available.  If an error occurs negotiating a watch with the server, the error is immediately return by the client `Watch()` method instead of being sent as an `Error`...

 
## Changes by Kind

### Deprecation

- #### Additional documentation e.g., KEPs (Kubernetes Enhancement Proposals), usage docs, etc.:
  
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### Feature

#### Dynamic Admission Control

* Pod spec is mutable when the pod is uninitialized. The API server requires the pod spec to be valid even if it's uninitialized. Updating the status field of uninitialized pods is invalid.([#51733](https://github.com/kubernetes/kubernetes/pull/51733))

  - *apiserver_cache_list_evaluated_objects_total*: Counter of objects tested in the course of serving a LIST request from watch cache, broken down by resource_prefix
  - *apiserver_cache_list_returned_objects_total*: Counter of objects returned for a LIST request from watch cache, broken down by resource_prefix

- Added ListMeta.RemainingItemCount. When responding to a LIST request, if the server has more data available, and if the request does not contain label selectors or field selectors, the server sets the ListOptions.RemainingItemCount to the number of remaining objects. ([#75993](https://github.com/kubernetes/kubernetes/pull/75993), [@caesarxuchao](https://github.com/caesarxuchao))

- Added a test to guarantee that conformance clusters require at least 2 untainted nodes. ([#106313](https://github.com/kubernetes/kubernetes/pull/106313), [@aojea](https://github.com/aojea))

WebhookConfiguration` so that webhooks can explicitly register as having dry-run support. If a dry-run request is made on a resource that triggers a non dry-run supporting webhook, the request will be completely rejected, with "400: Bad Request". Additionally, a new field is being added to the `admission.k8s.io/v1beta1.AdmissionReview` API object, exposing to webhooks whether or not the request being reviewed is a dry-run. ([#66936](https://github.com/kubernetes/kubernetes/pull/66936), [@jennybu...

- If the user specifies an invalid timeout in the request URL, the request will be aborted with an HTTP 400.

authentication now supports requiring specific claims with `--oidc-required-claim=<claim>=<value>` Previously, there was no mechanism for a user to specify claims in the OIDC authentication process that were requid to be present in the ID Token with an expected value. This version now makes it possible to require claims support for the OIDC authentication. It allows users to pass in a `--oidc-required-claims` flag, and `key=value` pairs in the API config, which will ensure that the specified required claims...