- 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]

- The new flag `--chunk-size=SIZE` for `kubectl drain` has been promoted to beta, and enabled by default. This flag  may be used to alter the number of items or disable this feature when `0` is passed. ([#100148](https://github.com/kubernetes/kubernetes/pull/100148), [@KnVerey](https://github.com/KnVerey))

  - 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]

  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`.

    - [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)

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

* Remove examples moved to docs site ([#23513](https://github.com/kubernetes/kubernetes/pull/23513), [@erictune](https://github.com/erictune))
* Do not query the metadata server to find out if running on GCE.  Retry metadata server query for gcr if running on gce. ([#28871](https://github.com/kubernetes/kubernetes/pull/28871), [@vishh](https://github.com/vishh))

- 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))

## Changelog since v1.15.3

### Other notable changes

* Restores compatibility with kubectl client-side validation when structural schemas are present in a CRD which sets spec.preserveUnknownFields=true ([#82666](https://github.com/kubernetes/kubernetes/pull/82666), [@liggitt](https://github.com/liggitt))