*     then this is not logically a {@code Converter} at all, and should just implement {@link
   *     Function}.
   */
  @ForOverride
  protected abstract A doBackward(B b);

  // API (consumer-side) methods

  /**
   * Returns a representation of {@code a} as an instance of type {@code B}.
   *
   * @return the converted value; is null <i>if and only if</i> {@code a} is null
   */

  - true/strict - perform validation and error the request on any invalid fields in the ojbect. It will attempt to perform server-side validation if it is enabled on the apiserver, otherwise it will fall back to client-side validation.

- Respect annotation size limit for server-side apply updates to the client-side apply annotation. Also, fix opt-out of this behavior by setting the client-side apply annotation to the empty string. ([#102105](https://github.com/kubernetes/kubernetes/pull/102105), [@julianvmodesto](https://github.com/julianvmodesto)) [SIG API Machinery]

- Dynamic Resource Allocation (DRA): client-side validation of a ResourceHandle would have accepted a missing DriverName, whereas server-side validation then would have raised an error. ([#124075](https://github.com/kubernetes/kubernetes/pull/124075), [@pohly](https://github.com/pohly))

  1. When configuring a dual-stack cluster, the user must specify both `--node-cidr-mask-size-ipv4` and `--node-cidr-mask-size-ipv6` to set the per-node IP mask sizes, instead of the previous `--node-cidr-mask-size` flag.
  2. The `--node-cidr-mask-size` flag is mutually exclusive with `--node-cidr-mask-size-ipv4` and `--node-cidr-mask-size-ipv6`.

- Respect annotation size limit for server-side apply updates to the client-side apply annotation. Also, fix opt-out of this behavior by setting the client-side apply annotation to the empty string. ([#102105](https://github.com/kubernetes/kubernetes/pull/102105), [@julianvmodesto](https://github.com/julianvmodesto)) [SIG API Machinery]

- Added `client-go` support for upgrading subresource fields from client-side to server-side management. ([#123484](https://github.com/kubernetes/kubernetes/pull/123484), [@erikgb](https://github.com/erikgb))

    - [Promoted CRD Validation Expression Language to Beta](#promoted-crd-validation-expression-language-to-beta)
    - [Promoted Server Side Unknown Field Validation to Beta](#promoted-server-side-unknown-field-validation-to-beta)
    - [Introduced KMS v2](#introduced-kms-v2)
    - [Kube-proxy images are now based on distroless images](#kube-proxy-images-are-now-based-on-distroless-images)

    * validation schemata as an alpha feature, to be enabled via the "CustomResourcePublishOpenAPI" feature gate. Kubectl will validate client-side using those. Note that in
    * future, client-side validation in 1.14 kubectl against a 1.15 cluster will reject
    * unknown fields for CRDs with validation schema defined. 

- The server-side apply feature is now beta ([#81956](https://github.com/kubernetes/kubernetes/pull/81956), [@apelisse](https://github.com/apelisse))