</p>

<p>
Type unification is controlled by a <i>matching mode</i>, which may
be <i>exact</i> or <i>loose</i>.
As unification recursively descends a composite type structure,
the matching mode used for elements of the type, the <i>element matching mode</i>,
remains the same as the matching mode except when two types are unified for

## Other notable changes
### API Machinery

- kube-apiserver: the `--runtime-config` flag now supports an `api/beta=false` value which disables all built-in REST API versions matching `v[0-9]+beta[0-9]+`. ([#84304](https://github.com/kubernetes/kubernetes/pull/84304), [@liggitt](https://github.com/liggitt))

 - Kubeadm: remove the automatic detection and matching of cgroup drivers for Docker. For new clusters if you have not configured the cgroup driver explicitly you might get a failure in the `kubelet` on driver mismatch (kubeadm clusters should be using the `systemd` driver). Also remove the `IsDockerSystemdCheck`...

* kubectl port-forward now allows using resource name (e.g., deployment/www) to select a matching pod, as well as the use of --pod-running-timeout to wait until at least one pod is running. ([#59705](https://github.com/kubernetes/kubernetes/pull/59705), [@phsiao](https://github.com/phsiao))

- Supporting Cross RG resources (disks, Azure File and node [Experimental]

Besides the above new features, support for Azure Virtual Machine Scale Sets (VMSS) and Cluster-Autoscaler is now stable and considered GA:

- Azure virtual machine scale sets (VMSS) allow you to create and manage identical load balanced VMs that automatically increase or decrease based on demand or a set schedule.

- Added CEL runtime cost calculation into ValidatingAdmissionPolicy, matching the evaluation cost
  restrictions that already apply to CustomResourceDefinition.
  If rule evaluation uses more compute than the limit, the API server aborts the evaluation and the

### **Instrumentation**

#### **Audit**

*   Adjust batching audit webhook default parameters: increase queue size, batch size, and initial backoff. Add throttling to the batching audit webhook. Default rate limit is 10 QPS. ([#53417](https://github.com/kubernetes/kubernetes/pull/53417),[ @crassirostris](https://github.com/crassirostris))

- The calculations for Pod topology spread skew now exclude nodes that
  don't match the node affinity/selector. This may lead to unschedulable pods if you previously had pods
  matching the spreading selector on those excluded nodes (not matching the node affinity/selector),
  especially when the `topologyKey` is not node-level. Revisit the node affinity and/or pod selector in the

#### Cluster Selection
* [alpha] Federation [ClusterSelector annotation](https://kubernetes.io/docs/tasks/administer-federation/cluster/#clusterselector-annotation) to direct objects to federated clusters with matching labels.


### **Instrumentation**
#### Core Metrics API

* Webhook always retries connection reset error. ([#53947](https://github.com/kubernetes/kubernetes/pull/53947), [@crassirostris](https://github.com/crassirostris))
* Adjust batching audit webhook default parameters: increase queue size, batch size, and initial backoff. Add throttling to the batching audit webhook. Default rate limit is 10 QPS. ([#53417](https://github.com/kubernetes/kubernetes/pull/53417), [@crassirostris](https://github.com/crassirostris))