* CustomResourceDefinitions: OpenAPI v3 validation schemas containing `$ref`references are no longer permitted (valid references could not be constructed previously because property ids were not permitted either). Before upgrading, ensure CRD definitions do not include those `$ref` fields. ([#58438](https://github.com/kubernetes/kubernetes/pull/58438),...

### Other notable changes

### Kubernetes API Reference Documentation

The API reference is now generated with [`gen-resourcesdocs`](https://github.com/kubernetes-sigs/reference-docs/tree/c96658d89fb21037b7d00d27e6dbbe6b32375837/gen-resourcesdocs) and it is moving to [Kubernetes API](https://docs.k8s.io/reference/kubernetes-api/)

### Kustomize Updates in Kubectl

- client-go releases will no longer have bootstrap (k8s.io/client-go/tools/bootstrap) related code. Any reference to it will break. Please redirect all references to k8s.io/bootstrap instead. ([#67356](https://github.com/kubernetes/kubernetes/pull/67356), [@yliaog](https://github.com/yliaog))

  in the time specified by `--legacy-service-account-token-clean-up-period` (defaulting
  to one year), **and are** referenced from the `.secrets` list of a ServiceAccount
  object, **and are not** referenced from pods. ([#115554](https://github.com/kubernetes/kubernetes/pull/115554), [@yt2985](https://github.com/yt2985))

  
  When adding links which point to resources within git repositories, like
  KEPs or supporting documentation, please reference a specific commit and avoid
  linking directly to the master branch. This ensures that links reference a
  specific point in time, rather than a document that may change over time.
  

When adding links which point to resources within git repositories, like
KEPs or supporting documentation, please reference a specific commit and avoid
linking directly to the master branch. This ensures that links reference a
specific point in time, rather than a document that may change over time.

* The OwnerReferencesPermissionEnforcement admission plugin now requires `update` permission on the `finalizers` subresource of the referenced owner in order to set `blockOwnerDeletion` on an owner reference. ([#49133](https://github.com/kubernetes/kubernetes/pull/49133), [@deads2k](https://github.com/deads2k))

- Reverts breaking change to inline AzureFile volumes in v1.18.15-v1.18.17; referenced secrets are now correctly searched for in the same namespace as the pod as in previous releases. ([#100397](https://github.com/kubernetes/kubernetes/pull/100397), [@andyzhangx](https://github.com/andyzhangx)) [SIG Cloud Provider and Storage]

  
  When adding links which point to resources within git repositories, like
  KEPs or supporting documentation, please reference a specific commit and avoid
  linking directly to the master branch. This ensures that links reference a
  specific point in time, rather than a document that may change over time.