- Clients should reload the token from disk periodically (once per minute is recommended) to ensure they continue to use a valid token. `k8s.io/client-go` version v11.0.0+ and v0.15.0+ reload tokens automatically.

- Added warnings about workload resources (Pods, ReplicaSets, Deployments, Jobs, CronJobs, or ReplicationControllers) whose names are not valid DNS labels. ([#114412](https://github.com/kubernetes/kubernetes/pull/114412), [@thockin](https://github.com/thockin))

    * Reduce logging agent buffer chunk limit to 512k to optimize performance.

* Add ipset and udevadm to the hyperkube base image. ([#61357](https://github.com/kubernetes/kubernetes/pull/61357), [@rphillips](https://github.com/rphillips))
* Fixes bugs that make apiserver panic when aggregating valid but not well formed OpenAPI spec ([#63626](https://github.com/kubernetes/kubernetes/pull/63626), [@roycaihw](https://github.com/roycaihw))

* Fixes bugs that make apiserver panic when aggregating valid but not well formed OpenAPI spec ([#63635](https://github.com/kubernetes/kubernetes/pull/63635), [@roycaihw](https://github.com/roycaihw))

  - path definitions added a `pathType` field to allow indicating how the specified path should be matched against incoming requests. Valid values are `Exact`, `Prefix`, and `ImplementationSpecific` ([#88587](https://github.com/kubernetes/kubernetes/pull/88587), [@cmluciano](https://github.com/cmluciano)) [SIG Apps, Cluster Lifecycle and Network]

- Client-go: make generated CA certificates valid 1 hour in the past (NewSelfSignedCACert). Applies to CA certificates and other certificates generated by kubeadm. ([#118631](https://github.com/kubernetes/kubernetes/pull/118631), [@champtar](https://github.com/champtar)) [SIG Auth]

## Changelog since v1.13.10

### Other notable changes

* Fix a bug in apiserver that could cause a valid update request to be rejected with a precondition check failure. ([#82303](https://github.com/kubernetes/kubernetes/pull/82303), [@roycaihw](https://github.com/roycaihw))

- Fixed StatefulSet to show the valid status even if the new replica creation fails. ([#112084](https://github.com/kubernetes/kubernetes/pull/112084), [@gjkim42](https://github.com/gjkim42)) [SIG Apps and Testing]

- Support `controlplane` as a valid EgressSelection type in the EgressSelectorConfiguration API. `Master` is deprecated and will be removed in v1.22. ([#95235](https://github.com/kubernetes/kubernetes/pull/95235), [@andrewsykim](https://github.com/andrewsykim)) [SIG API Machinery]