## API Changes
- CustomResourceDefinitions now validate documented API semantics of `x-kubernetes-list-type` and `x-kubernetes-map-type` atomic to reject non-atomic sub-types. ([#84722](https://github.com/kubernetes/kubernetes/pull/84722), [@sttts](https://github.com/sttts))

JSON API clients should tolerate `null` values for such fields, and treat `null` and `[]` as equivalent in meaning unless specifically documented otherwise for a particular field. ([#44593](https://github.com/kubernetes/kubernetes/pull/44593))

- Fixes bug where an incomplete OpenAPI V3 document can cause a nil-pointer crash.
  Ensures fallback to OpenAPI V2 endpoint for errors retrieving OpenAPI V3 document. ([#117918](https://github.com/kubernetes/kubernetes/pull/117918), [@seans3](https://github.com/seans3)) [SIG CLI]

* In-tree support for openstack credentials is now deprecated. please use the "client-keystone-auth" from the cloud-provider-openstack repository. details on how to use this new capability is documented [here](https://github.com/kubernetes/cloud-provider-openstack/blob/master/docs/using-client-keystone-auth.md) ([#64346](https://github.com/kubernetes/kubernetes/pull/64346), [@dims](https://github.com/dims))

- Kube-apiserver: Defaulted empty `spec.jobTemplate.spec.podFailurePolicy.rules[*].onPodConditions[*].status` fields for CronJob objects as documented, avoiding validation failures during write requests. ([#131525](https://github.com/kubernetes/kubernetes/pull/131525), [@carlory](https://github.com/carlory))

- Documented the `--for=create` option to `kubectl wait`. ([#127327](https://github.com/kubernetes/kubernetes/pull/127327), [@ryanwinter](https://github.com/ryanwinter)) [SIG CLI]

  - Health check (liveness & readiness) probes using an HTTPGetAction will no longer follow redirects to different hostnames from the original probe request. Instead, these non-local redirects will be treated as a Success (the documented behavior). In this case an event with reason "ProbeWarning" will be generated, indicating that the redirect was ignored. If you were previously relying on the redirect to run health checks against different endpoints, you will need to perform the...

* Exclude nodes labeled as master from LoadBalancer / NodePort; restores documented behaviour. ([#44745](https://github.com/kubernetes/kubernetes/pull/44745), [@justinsb](https://github.com/justinsb))

- Protobuf serialization of metav1.MicroTime timestamps (used in `Lease` and `Event` API objects) has been corrected to truncate to microsecond precision, to match the documented behavior and JSON/YAML serialization. Any existing persisted data is truncated to microsecond when read from etcd. ([#111936](https://github.com/kubernetes/kubernetes/pull/111936), [@haoruan](https://github.com/haoruan))

## Changes by Kind

### API Change

- Protobuf serialization of metav1.MicroTime timestamps (used in `Lease` and `Event` API objects) has been corrected to truncate to microsecond precision, to match the documented behavior and JSON/YAML serialization. Any existing persisted data is truncated to microsecond when read from etcd. ([#111936](https://github.com/kubernetes/kubernetes/pull/111936), [@haoruan](https://github.com/haoruan)) [SIG API Machinery]