* The shortcuts that were moved server-side in at least 1.9 have been removed from being hardcoded in kubectl. This means that the client-based restmappers have been moved to client-go, where everyone who needs them can have access. ([#63507](https://github.com/kubernetes/kubernetes/pull/63507), [@deads2k](https://github.com/deads2k))

  * 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...

- The helping message of commands which have sub-commands is now clearer and more instructive. It will show the full command instead of `kubectl <command>...

  - [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)

### Other notable changes

* hyperkube: add cloud-controller-manager ([#54197](https://github.com/kubernetes/kubernetes/pull/54197), [@colemickens](https://github.com/colemickens))

* Azure: Container permissions for provisioned volumes have changed to private. If you have existing Azure volumes that were created by Kubernetes v1.6.0-v1.6.5, you should change the permissions on them manually. ([#47605](https://github.com/kubernetes/kubernetes/pull/47605), [@brendandburns](https://github.com/brendandburns))

* The metrics APIs, `custom-metrics.metrics.k8s.io` and `metrics`, were moved from `v1alpha1` to `v1beta1`, and renamed to `custom.metrics.k8s.io` and `metrics.k8s.io`, respectively. If you have deployed a custom metrics adapter, ensure that it supports the new API version. If you have deployed Heapster in aggregated API server mode, upgrade Heapster to support the latest API version.

- **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).

- [`KTIJ-24768`](https://youtrack.jetbrains.com/issue/KTIJ-24768) IDE K2: "IllegalArgumentException Failed requirement at FirJvmTypeMapper"
- [`KT-56845`](https://youtrack.jetbrains.com/issue/KT-56845) Light classes: Overridden property accessors don't have `@Override` annotation

- Kubelet metrics have been changed to buckets. 
  For example the exec/{podNamespace}/{podID}/{containerName} is now just exec. ([#87913](https://github.com/kubernetes/kubernetes/pull/87913), [@cheftako](https://github.com/cheftako)) [SIG Node]