- [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)

* 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))

methods in generated clientsets, dynamic, metadata, and scale clients have been modified to accept `context.Context` as a first argument. Signatures of Create, Update, and Patch methods have been updated to accept CreateOptions, UpdateOptions and PatchOptions respectively. Signatures of Delete and DeleteCollection methods now accept DeleteOptions by value instead of by reference. Generated clientsets with the previous interface have been added in new "deprecated" packages to allow incremental migration...

### Other notable changes

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

- 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>...

* 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))

- **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).

accidental enablement of the new alpha `optionalOldSelf` API field in CustomResourceDefinition validation rules, which should only be allowed to be set when the CRDValidationRatcheting feature gate is enabled. Existing CustomResourceDefinition objects which have the field set will retain it on update, but new CustomResourceDefinition objects will not be permitted to set the field while the CRDValidationRatcheting feature gate is disabled. ([#122343](https://github.com/kubernetes/kubernetes/pull/122343), [...

- 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 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`.