* CustomResourceDefinitions: OpenAPI v3 validation schemas containing `$ref`references are no longer permitted. Before upgrading, ensure CRD definitions do not include those `$ref` fields. ([#58438](https://github.com/kubernetes/kubernetes/pull/58438), [@carlory](https://github.com/carlory))

- Restores compatibility with <=1.15.x custom resources by not publishing OpenAPI for non-structural custom resource definitions ([#82653](https://github.com/kubernetes/kubernetes/pull/82653), [@liggitt](https://github.com/liggitt))

  - The OpenAPI definitions with the prefix "io.k8s.kubernetes.pkg" (deprecated since 1.9) have been removed. ([#74596](https://github.com/kubernetes/kubernetes/pull/74596), [@sttts](https://github.com/sttts))

- Ingress:
  - `spec.ingressClassName` replaces the deprecated `kubernetes.io/ingress.class` annotation, and allows associating an Ingress object with a particular controller.

- OpenAPI definitions served by kube-apiserver now include enum types by default. ([#108898](https://github.com/kubernetes/kubernetes/pull/108898), [@jiahuif](https://github.com/jiahuif))

- `kubectl rollout restart` now works for DaemonSets and StatefulSets. ([#77423](https://github.com/kubernetes/kubernetes/pull/77423), [@apelisse](https://github.com/apelisse))
- `kubectl get --watch=true` now prints custom resource definitions with custom print columns. ([#76161](https://github.com/kubernetes/kubernetes/pull/76161), [@liggitt](https://github.com/liggitt))

- API paging is now enabled for custom resource definitions, custom resources and APIService objects. ([#67861](https://github.com/kubernetes/kubernetes/pull/67861), [@liggitt](https://github.com/liggitt))

  }

  /**
   * A sensible definition of {@link #contains} in terms of {@link #count}. If you override {@link
   * #count}, you may wish to override {@link #contains} to forward to this implementation.
   *
   * @since 7.0
   */
  @Override
  protected boolean standardContains(@Nullable Object object) {
    return count(object) > 0;
  }

  /**

  }

  /**
   * A sensible definition of {@link #hashCode} in terms of the {@code iterator} method of {@link
   * #entrySet}. If you override {@link #entrySet}, you may wish to override {@link #hashCode} to
   * forward to this implementation.
   *
   * @since 7.0
   */
  protected int standardHashCode() {
    return Sets.hashCodeImpl(entrySet());
  }

  /**

  }

  /**
   * A sensible definition of {@link #contains} in terms of {@link #count}. If you override {@link
   * #count}, you may wish to override {@link #contains} to forward to this implementation.
   *
   * @since 7.0
   */
  @Override
  protected boolean standardContains(@Nullable Object object) {
    return count(object) > 0;
  }

  /**