* A pod never terminated if a container image registry was unavailable ([#23746](https://github.com/kubernetes/kubernetes/pull/23746), [@derekwaynecarr](https://github.com/derekwaynecarr))

labels.ignore_failure_type=Ignore Failure Types
labels.failure_count_threshold=Failure Count Threshold
labels.popular_word_word_enabled=Popular Word Response
labels.supported_search_web=Web
labels.supported_search_none=Unavailable
labels.purge_search_log_day=Delete old search logs
labels.purge_job_log_day=Delete old job logs
labels.purge_user_info_day=Delete old user logs
labels.purge_by_bots=Bot names to delete logs
labels.log_level=Log Level

    behavior was deprecated with RFC 2818 in May 2000 and was recently dropped
    from major web browsers.
 *  New: Honor the `Retry-After` response header. HTTP 503 (Unavailable)
    responses are retried automatically if this header is present and its delay
    is 0 seconds. HTTP 408 (Client Timeout) responses are retried automatically
    if the header is absent or its delay is 0 seconds.

- kube-apiserver now includes all registered API groups in discovery, including registered extension API group/versions for unavailable extension API servers. ([#66932](https://github.com/kubernetes/kubernetes/pull/66932), [@nilebox](https://github.com/nilebox))

  - NetworkPolicy resources will no longer be served from `extensions/v1beta1` in v1.16. Migrate use to the `networking.k8s.io/v1` API, available since v1.8. Existing persisted data can be retrieved via the `networking.k8s.io/v1` API.

- Removed generally available feature gate `CSINodeExpandSecret`. ([#124462](https://github.com/kubernetes/kubernetes/pull/124462), [@carlory](https://github.com/carlory))
- Removed generally available feature gate `ConsistentHTTPGetHandlers`. ([#124463](https://github.com/kubernetes/kubernetes/pull/124463), [@carlory](https://github.com/carlory))

## Changes by Kind

### API Change

- Make STS available replicas optional again, ([#109241](https://github.com/kubernetes/kubernetes/pull/109241), [@ravisantoshgudimetla](https://github.com/ravisantoshgudimetla)) [SIG API Machinery and Apps]

   * OpenSSL CVE fixes
* ContainerVm/GCI image: try to use ifdown/ifup if available ([#33595](https://github.com/kubernetes/kubernetes/pull/33595), [@freehan](https://github.com/freehan))
* Make the informer library available for the go client library. ([#32718](https://github.com/kubernetes/kubernetes/pull/32718), [@mikedanese](https://github.com/mikedanese))

* kube-apiserver: requests to endpoints handled by unavailable extension API servers (as indicated by an `Available` condition of `false` in the registered APIService) now return `503` errors instead of `404` errors. ([#58070](https://github.com/kubernetes/kubernetes/pull/58070), [@weekface](https://github.com/weekface))

* [alpha] Make locally attached (non-network attached) storage available as a persistent volume source. For more information, see [Storage Volumes - local](https://kubernetes.io/docs/concepts/storage/volumes/#local).

#### Volume Plugins