* The OpenID Connect authenticator can now use a custom prefix, or omit the default prefix, for username and groups claims through the --oidc-username-prefix and --oidc-groups-prefix flags. For example, the authenticator can map a user with the username "jane" to "google:jane" by supplying the "google:" username prefix. ([#50875](https://github.com/kubernetes/kubernetes/pull/50875), [@ericchiang](https://github.com/ericchiang))

## Changelog since v1.13.4

### Other notable changes

* Restores --username and --password flags to kubectl ([#75451](https://github.com/kubernetes/kubernetes/pull/75451), [@liggitt](https://github.com/liggitt))

* Node-Problem-Detector configuration is now decoupled from the Kubernetes release on GKE/GCE. ([#73288](https://github.com/kubernetes/kubernetes/pull/73288), [@wangzhen127](https://github.com/wangzhen127))
* Restores --username and --password flags to kubectl ([#75451](https://github.com/kubernetes/kubernetes/pull/75451), [@liggitt](https://github.com/liggitt))

* Restores --username and --password flags to kubectl ([#75451](https://github.com/kubernetes/kubernetes/pull/75451), [@liggitt](https://github.com/liggitt))

* The OpenID Connect authenticator can now use a custom prefix, or omit the default prefix, for username and groups claims through the --oidc-username-prefix and --oidc-groups-prefix flags. For example, the authenticator can map a user with the username "jane" to "google:jane" by supplying the "google:" username prefix. ([#50875](https://github.com/kubernetes/kubernetes/pull/50875), [@ericchiang](https://github.com/ericchiang))

  * kube-apiserver learned the '--anonymous-auth' flag, which defaults to true. When enabled, requests to the secure port that are not rejected by other configured authentication methods are treated as anonymous requests, and given a username of 'system:anonymous' and a group of 'system:unauthenticated'.
  * Authenticated users are decorated with a 'system:authenticated' group.
  * **IMPORTANT**: See Action Required for important actions related to this change.

- Use checksums instead of fsyncs to ensure discovery cache integrity ([#110851](https://github.com/kubernetes/kubernetes/pull/110851), [@negz](https://github.com/negz)) [SIG API Machinery]
- UserName check for 'ContainerAdministrator' is now case-insensitive if runAsNonRoot is set to true on Windows. ([#111009](https://github.com/kubernetes/kubernetes/pull/111009), [@marosset](https://github.com/marosset))

- UserName check for 'ContainerAdministrator' is now case-insensitive if runAsNonRoot is set to true on Windows. ([#112212](https://github.com/kubernetes/kubernetes/pull/112212), [@PushkarJ](https://github.com/PushkarJ)) [SIG Node, Testing and Windows]

- UserName check for 'ContainerAdministrator' is now case-insensitive if runAsNonRoot is set to true on Windows. ([#112213](https://github.com/kubernetes/kubernetes/pull/112213), [@PushkarJ](https://github.com/PushkarJ)) [SIG Node, Testing and Windows]

- UserName check for 'ContainerAdministrator' is now case-insensitive if runAsNonRoot is set to true on Windows. ([#112211](https://github.com/kubernetes/kubernetes/pull/112211), [@PushkarJ](https://github.com/PushkarJ)) [SIG Node, Testing and Windows]