- Users might specify the `kubectl.kubernetes.io/default-container` annotation in a Pod to...

- Kube-proxy: on dual-stack mode, if it is not able to get the IP Family of an endpoint, logs it with level InfoV(4) instead of Warning, avoiding flooding the logs for endpoints without addresses ([#88934](https://github.com/kubernetes/kubernetes/pull/88934), [@aojea](https://github.com/aojea)) [SIG Network]

* Increase allowed lag for ssh key sync loop in tunneler to allow for one failure ([#60068](https://github.com/kubernetes/kubernetes/pull/60068), [@wojtek-t](https://github.com/wojtek-t))
* Fixing a bug in OpenStack cloud provider, where dual stack deployments (IPv4 and IPv6) did not work well when using kubenet as the network plugin. ([#59749](https://github.com/kubernetes/kubernetes/pull/59749), [@zioproto](https://github.com/zioproto))

### OpenStack

* Fixed a bug in the OpenStack cloud provider where dual stack deployments (IPv4 and IPv6) did not work well when using kubenet as the network plugin. ([#59749](https://github.com/kubernetes/kubernetes/pull/59749), [@zioproto](https://github.com/zioproto))

- Fixed stuck apiserver if an aggregated apiservice returned `304 Not Modified` for aggregated discovery information ([#114459](https://github.com/kubernetes/kubernetes/pull/114459), [@alexzielenski](https://github.com/alexzielenski))

- Fixed a regression in kube-proxy where it might refuse to start if given
  single-stack IPv6 configuration options on a node that has both IPv4 and
  IPv6 IPs. ([#121008](https://github.com/kubernetes/kubernetes/pull/121008), [@danwinship](https://github.com/danwinship)) [SIG Network]

* Ensure Azure load balancer cleaned up on 404 or 403 when deleting LoadBalancer services. ([#75256](https://github.com/kubernetes/kubernetes/pull/75256), [@feiskyer](https://github.com/feiskyer))
* Fix kubelet start failure issue on Azure Stack due to InstanceMetadata setting ([#74936](https://github.com/kubernetes/kubernetes/pull/74936), [@rjaini](https://github.com/rjaini))

* Update dashboard version to v1.8.3 ([#57326](https://github.com/kubernetes/kubernetes/pull/57326), [@floreks](https://github.com/floreks))
* Fixes a case when Deployment with recreate strategy could get stuck on old failed Pod. ([#60496](https://github.com/kubernetes/kubernetes/pull/60496), [@tnozicka](https://github.com/tnozicka))

### IPv4/IPv6 run

IPv4/IPv6 dual-stack has been reimplemented for 1.20 to support dual-stack Services, based on user and community feedback. If your cluster has dual-stack enabled, you can create Services which can use IPv4, IPv6, or both, and you can change this setting for existing Services. Details are available in updated [IPv4/IPv6 dual-stack docs](https://docs.k8s.io/concepts/services-networking/dual-stack/), which cover the nuanced array of options.

### IPv4/IPv6 Dual-stack Networking graduates to GA

[IPv4/IPv6 dual-stack networking](https://github.com/kubernetes/enhancements/tree/master/keps/sig-network/563-dual-stack) graduates to GA.
Since 1.21, Kubernetes clusters are enabled to support dual-stack networking by default.
In 1.23, the `IPv6DualStack` feature gate is removed.
The use of dual-stack networking is not mandatory.