- New flag `--show-hidden-metrics-for-version` in kube-proxy, kubelet, kube-controller-manager, and kube-scheduler can be used to show all hidden metrics that are deprecated in the previous minor release. ([#85279](https://github.com/kubernetes/kubernetes/pull/85279), [@RainbowMango](https://github.com/RainbowMango)) [SIG Cluster Lifecycle and Network]

#### Features graduated to beta:

- The RuntimeClass scheduler can now simplify steering Linux or Windows pods to appropriate nodes
- All Windows nodes now get the new label `node.kubernetes.io/windows-build` that reflects the Windows major, minor, and build number that are needed to match compatibility between Windows containers and Windows worker nodes.


## Deprecations and Removals

* Corrected a mistake in the documentation for wait.PollImmediate(...) ([#65026](https://github.com/kubernetes/kubernetes/pull/65026), [@spew](https://github.com/spew))
* Split 'scheduling_latency_seconds' metric into finer steps (predicate, priority, premption) ([#65306](https://github.com/kubernetes/kubernetes/pull/65306), [@shyamjvs](https://github.com/shyamjvs))

* addon-resizer flapping behavior was removed. ([#46850](https://github.com/kubernetes/kubernetes/pull/46850), [@x13n](https://github.com/x13n))
* Change default `httpGet` probe `User-Agent` to `kube-probe/<version major.minor>` if none specified, overriding the default Go `User-Agent`. ([#47729](https://github.com/kubernetes/kubernetes/pull/47729), [@paultyng](https://github.com/paultyng))

- Kubectl version changed to write a warning message to stderr if the client and server version difference exceeds the supported version skew of +/-1 minor version. ([#98250](https://github.com/kubernetes/kubernetes/pull/98250), [@brianpursley](https://github.com/brianpursley)) [SIG CLI]

* fixes configuration error when upgrading kubeadm from 1.9 to 1.10+ ([#62568](https://github.com/kubernetes/kubernetes/pull/62568), [@liztio](https://github.com/liztio))
    * enforces  kubeadm  upgrading kubernetes from the same major and minor versions as the kubeadm binary.
* Bugfix allowing use of IP-aliases with custom-mode network in GCE setup scripts. ([#62172](https://github.com/kubernetes/kubernetes/pull/62172), [@shyamjvs](https://github.com/shyamjvs))

* Add automatic etcd 3.2->3.1 and 3.1->3.0 minor version rollback support to gcr.io/google_container/etcd images. For HA clusters, all members must be stopped before performing a rollback. ([#59298](https://github.com/kubernetes/kubernetes/pull/59298), [@jpbetz](https://github.com/jpbetz))

* kubectl: This client version requires the `apps/v1` APIs, so it will not work against a cluster version older than v1.9.0. Note that kubectl only guarantees compatibility with clusters that are +/-1 minor version away. ([#61419](https://github.com/kubernetes/kubernetes/pull/61419), [@enisoc](https://github.com/enisoc))

### SIG Network

For 1.13, the areas of focus were in IPv6, DNS improvements and some smaller items:

* Protobuf serialization does not distinguish between `[]` and `null`.