- The deprecated kube-controller-manager flag '--deployment-controller-sync-period' has been removed, it is not used by the deployment controller. ([#107178](https://github.com/kubernetes/kubernetes/pull/107178), [@SataQiu](https://github.com/SataQiu))

- kubeadm

  - The CoreDNS Deployment now checks readiness via the `ready` plugin.
  - The `proxy` plugin has been deprecated. The `forward` plugin is to be used instead.
  - `kubernetes` plugin removes the `resyncperiod` option.

#### AWS

- The `system:aws-cloud-provider` cluster role, deprecated in v1.13, is no longer auto-created. Deployments using the AWS cloud provider should grant required permissions to the `aws-cloud-provider` service account in the `kube-system` namespace as part of deployment.  ([#66635](https://github.com/kubernetes/kubernetes/pull/66635), [@wgliang](https://github.com/wgliang))

#### Azure

  PodSubnet validates against the corresponding cluster "--node-cidr-mask-size" of the kube-controller-manager, it fail if the values are not compatible.
  kubeadm no longer sets the node-mask automatically on IPv6 deployments, you must check that your IPv6 service subnet mask is compatible with the default node mask /64 or set it accordingly.

- The TopologySpreadConstraints will be shown in describe command for pods, deployments, daemonsets, etc. ([#109563](https://github.com/kubernetes/kubernetes/pull/109563), [@ardaguclu](https://github.com/ardaguclu))

  select the same set of Pods, scaling now will be disabled for those HPAs with
  the reason `AmbiguousSelector`. This change also covers a case when multiple HPAs
  point to the same deployment.'
   ([#112011](https://github.com/kubernetes/kubernetes/pull/112011), [@pbeschetnov](https://github.com/pbeschetnov))
- 'Pod Security admission: the pod-security `warn` level will now default to
  the `enforce` level.'

### Documentation

- Added descriptions and examples for the situation of using `kubectl rollout restart` without specifying a particular deployment. ([#120118](https://github.com/kubernetes/kubernetes/pull/120118), [@Ithrael](https://github.com/Ithrael))

  - PodSecurityPolicy resources will no longer be served from `extensions/v1beta1` in v1.16. Migrate to the `policy/v1beta1` API, available since v1.10. Existing persisted data can be retrieved via the `policy/v1beta1` API.
  - DaemonSet, Deployment, and ReplicaSet resources will no longer be served from `extensions/v1beta1`, `apps/v1beta1`, or `apps/v1beta2` in v1.16. Migrate to the `apps/v1` API, available since v1.9. Existing persisted data can be retrieved via the `apps/v1` API.