* Services of type=LoadBalancer which have no endpoints will now immediately ICMP reject connections, rather than time out. ([#74394](https://github.com/kubernetes/kubernetes/pull/74394), [@thockin](https://github.com/thockin))

- Newly provisioned PVs by vSphere in-tree plugin will no longer have the beta FailureDomain label. vSphere volume plugin will start to have GA topology label instead. ([#102414](https://github.com/kubernetes/kubernetes/pull/102414), [@divyenpatel](https://github.com/divyenpatel)) [SIG Cloud Provider, Storage and Testing]

- Kubeadm: external etcd endpoints passed in the `ClusterConfiguration` that have Unicode characters are no longer IDNA encoded (converted to Punycode). They are now just URL encoded as per Go's implementation of RFC-3986, have duplicate "/" removed from the URL paths, and passed like that directly to the `kube-apiserver` `--etcd-servers` flag. If you have etcd endpoints that have Unicode characters, it is advisable to encode them in advance with tooling that is fully IDNA compliant....

  - [Known Issues](#known-issues)
    - [Summary API in kubelet doesn't have accelerator metrics](#summary-api-in-kubelet-doesnt-have-accelerator-metrics)
  - [Urgent Upgrade Notes](#urgent-upgrade-notes)
    - [(No, really, you MUST read this before you upgrade)](#no-really-you-must-read-this-before-you-upgrade)

- **Custom resources:** CRDs are in widespread use as a way to extend Kubernetes to persist and serve new resource types, and have been available in beta since the 1.7 release. The 1.16 release marks the graduation of CRDs to general availability (GA).

- The feature gate was mentioned as `csiMigrationRBD` where it should have been `CSIMigrationRBD` to be in parity with other migration plugins. This release correct the same and keep it as `CSIMigrationRBD`.

graduated the kubeadm specific feature gate `UnversionedKubeletConfigMap` to GA and locked it to `true` by default. The kubelet related ConfigMap and RBAC rules are now locked to have a simplified naming `*kubelet-config` instead of the legacy naming `*kubelet-config-x.yy`, where `x.yy` was the version of the control plane. If you have previously used the old naming format with `UnversionedKubeletConfigMap=false`, you must manually copy the config map from `kube-system/kubelet-config-x.yy` to `kube-system/kubelet-config`...

  * You can find out what taints you have in place on a node while you are still running Kubernetes 1.5 by doing `kubectl describe node <node name>`; the `Taints` section will show the taints you have in place. To see the taints that were created under 1.5 when you are running 1.6, do `kubectl get node <node name> -o yaml` and look for the...

- Fixed `threadSafeMap` high memory usage caused by indices that have churn of high-cardinality keys. E.g. namespaces ([#88005](https://github.com/kubernetes/kubernetes/pull/88005), [@patrickshan](https://github.com/patrickshan)) [SIG API Machinery]

  - The `/swaggerapi/*` schema docs, deprecated since 1.7, have been removed in favor of the /openapi/v2 schema docs. ([#72924](https://github.com/kubernetes/kubernetes/pull/72924), [@liggitt](https://github.com/liggitt))