* Change default clusterCIDRs from /16 to /14 in GCE configs allowing 1000 Node clusters by default. ([#25350](https://github.com/kubernetes/kubernetes/pull/25350), [@gmarek](https://github.com/gmarek))

- Avoid marking node as Ready until node has synced with API servers at least once ([#99034](https://github.com/kubernetes/kubernetes/pull/99034), [@ehashman](https://github.com/ehashman)) [SIG Node]
- Cleanup subnet in frontend IP configs to prevent huge subnet request bodies in some scenarios. ([#98290](https://github.com/kubernetes/kubernetes/pull/98290), [@nilo19](https://github.com/nilo19)) [SIG Cloud Provider]

      kind: ConfigMap
      apiVersion: v1
      metadata:
        name: kube-dns
        namespace: kube-system
      data:
        federations: abc=def
      ```
* azure: support multiple ipconfigs on a NIC ([#36841](https://github.com/kubernetes/kubernetes/pull/36841), [@colemickens](https://github.com/colemickens))

* kubeadm: Control plane component configs are separated into ClusterConfiguration sub-structs. ([#70371](https://github.com/kubernetes/kubernetes/pull/70371), [@rosti](https://github.com/rosti))

- kubeadm no longer allows using v1alpha3 configs for anything else than converting them to `v1beta1`. ([#74025](https://github.com/kubernetes/kubernetes/pull/74025), [@rosti](https://github.com/rosti))

* Fixed a bug where the --server, --token, and --certificate-authority flags were not overriding the related in-cluster configs when provided in a `kubectl` call inside a cluster. ([#39006](https://github.com/kubernetes/kubernetes/pull/39006), [@fabianofranz](https://github.com/fabianofranz))

#### Other Notable Changes

- kubeadm: Default component configs are now printable via kubeadm config print-default ([#66074](https://github.com/kubernetes/kubernetes/pull/66074), [@rosti](https://github.com/rosti)) Courtesy of SIG Cluster Lifecycle

skip cluster-scoped resources. Before upgrading your Kubernetes clusters, double check whether you have configured webhooks for cluster-scoped objects (e.g., nodes, persistentVolume), as these webhooks will start to take effect. Delete/modify the configs if that's not desirable. ([#58185](https://github.com/kubernetes/kubernetes/pull/58185), [@caesarxuchao](https://github.com/caesarxuchao))

* Using kubectl gcp auth plugin with a Google Service Account to authenticate to a cluster now...

- Cleanup subnet in frontend IP configs to prevent huge subnet request bodies in some scenarios. ([#98133](https://github.com/kubernetes/kubernetes/pull/98133), [@nilo19](https://github.com/nilo19)) [SIG Cloud Provider]

* There's a known issue where the Vertical Pod Autoscaler will radically change implementation in 1.12, so users of VPA (alpha) in 1.11 are warned that they will not be able to automatically migrate their VPA configs from 1.11 to 1.12.


## Before Upgrading