* An `automountServiceAccountToken` field was added to ServiceAccount and PodSpec objects. If set to `false` on a pod spec, no service account token is automounted in the pod. If set to `false` on a service account, no service account token is automounted for that service account unless explicitly overridden in the pod spec. ([#37953](https://github.com/kubernetes/kubernetes/pull/37953), [@ligg...

  - `resourceclaim_controller_creates_total` count metric with labels `admin_access` (true or false), `status` (failure or success) to track the total number of `ResourceClaims` creation requests

* Changes secret, configMap, downwardAPI and projected volumes to mount read-only, instead of allowing applications to write data and then reverting it automatically. Until version 1.11, setting the feature gate ReadOnlyAPIDataVolumes=false will preserve the old behavior. ([#58720](https://github.com/kubernetes/kubernetes/pull/58720), [@joelsmith](https://github.com/joelsmith))

* [IPVS] Introduces flag ipvs-strict-arp to configure stricter ARP sysctls, defaulting to false to preserve existing behaviors. This was enabled by default in 1.13.0, which impacted a few CNI plugins. ([#75295](https://github.com/kubernetes/kubernetes/pull/75295), [@lbernail](https://github.com/lbernail))

  * Bug fixes

    * Fix some false negatives in detection of meaningful conflicts during strategic merge patch with maps and lists. ([#43469](https://github.com/kubernetes/kubernetes/pull/43469), [@enisoc](https://github.com/enisoc))

 - [Action Required] CSI drivers that call IsLikelyNotMountPoint should not assume false means that the path is a mount point. Each CSI driver needs to make sure correct usage of return value of IsLikelyNotMountPoint because if the file is an irregular file but not a mount point is acceptable ([#129370](https://github.com/kubernetes/k...

  - Client-side (kubectl) feature gate: `KUBECTL_REMOTE_COMMAND_WEBSOCKETS`
  - To disable RemoteCommand over WebSockets for kubectl, the environment variable feature gate must be explicitly set to `false`: `KUBECTL_REMOTE_COMMAND_WEBSOCKETS=false`.
   ([#123281](https://github.com/kubernetes/kubernetes/pull/123281), [@seans3](https://github.com/seans3))

- Add CRD spec.preserveUnknownFields boolean, defaulting to true in v1beta1 and to false in v1 CRDs. If false, fields not specified in the validation schema will be removed when sent to the API server or when read from etcd. ([#77333](https://github.com/kubernetes/kubernetes/pull/77333), [@sttts](https://github.com/sttts))

### 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))

  Example: suppose you develop a custom plugin that denies Pods that have a `schedulable=false` label.