- Performance improvements in `klog` ([#115277](https://github.com/kubernetes/kubernetes/pull/115277), [@pohly](https://github.com/pohly))
- Pod template `schedulingGates` are now mutable for Jobs that are suspended and have never been started ([#115940](https://github.com/kubernetes/kubernetes/pull/115940), [@ahg-g](https://github.com/ahg-g)) [SIG Apps]

The external cloud provider was established and reached feature parity with in-tree, and we expect to stabilize it and have it as preferred deployment model by 1.13. We are also getting started on externalizing the vSphere volume functionalities in a CSI plugin to fully reproduce the current in-tree storage functionality.

- `-- kube-controller-manager`
  `--node-cidr-mask-size-ipv4 int32`     Default: 24. Mask size for IPv4 node-cidr in dual-stack cluster.
`--node-cidr-mask-size-ipv6 int32`     Default: 64. Mask size for IPv6 node-cidr in dual-stack cluster.

    These 2 flags can be used only for dual-stack clusters. For non dual-stack clusters, continue to use  `--node-cidr-mask-size` flag to configure the mask size.

* On AWS kubelet returns an error when started under conditions that do not allow it to work (AWS has not yet tagged the instance). ([#60125](https://github.com/kubernetes/kubernetes/pull/60125), [@vainu-arto](https://github.com/vainu-arto))

from v1beta3 and its management in the kube-system/kubeadm-config ConfigMap. This method of keeping track of what API endpoints exists in the cluster was replaced (in a prior release) by a method to annotate the etcd Pods that `kubeadm` creates in "stacked etcd" clusters. The following CLI sub-phases are deprecated and are now a NO-OP: for `kubeadm join`: "control-plane-join/update-status", for `kubeadm reset`: "update-cluster-status". Unless you are using these phases explicitly, you should not be...

- [IPv4/IPv6 dual-stack](https://kubernetes.io/docs/concepts/services-networking/dual-stack) enables the allocation of both IPv4 and IPv6 addresses to Pods and Services.

- Updated the API documentation for Service.Spec.IPFamily to warn that its exact
  semantics will probably change before the dual-stack feature goes GA, and users
  should look at ClusterIP or Endpoints, not IPFamily, to figure out if an existing
  Service is IPv4, IPv6, or dual-stack. ([#91527](https://github.com/kubernetes/kubernetes/pull/91527), [@danwinship](https://github.com/danwinship)) [SIG Apps and Network]

### 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.

## Changelog since v1.15.0

### Other notable changes

* kubeadm: implement support for concurrent add/remove of stacked etcd members ([#79677](https://github.com/kubernetes/kubernetes/pull/79677), [@neolit123](https://github.com/neolit123))

* **[alpha]** New Bootstrap Token authentication and management method. Works well with kubeadm. kubeadm now supports managing tokens, including time based expiration, after...