- The `IPTablesOwnershipCleanup` feature (KEP-3178) is now GA; kubelet no longer
  creates the `KUBE-MARK-DROP` chain (which has been unused for several releases)
  or the `KUBE-MARK-MASQ` chain (which is now only created by kube-proxy). ([#119374](https://github.com/kubernetes/kubernetes/pull/119374), [@danwinship](https://github.com/danwinship))

* Improved user experience for environments without a public internet connection and users using other CRI runtimes than Docker
* Support for structured configuration for the kubelet, which avoids the need to modify the systemd drop-in file
* Many improvements to the upgrade process and other bug fixes

### SIG Instrumentation

  for background information.

### Scheduling

  - Opaque Integer Resources (OIRs) are deprecated and will be removed in
    version 1.9. Extended Resources (ERs) are a drop-in replacement for OIRs. You can use
    any domain name prefix outside of the `kubernetes.io/` domain instead of the
    `pod.alpha.kubernetes.io/opaque-int-resource-` prefix.

## Notable Features

* Fix bug where EndpointSlice controller would attempt to modify shared objects. ([#85368](https://github.com/kubernetes/kubernetes/pull/85368), [@robscott](https://github.com/robscott))
* Revert ensure the KUBE-MARK-DROP chain in kube-proxy mode=iptables. Fix a bug in which kube-proxy deletes the rules associated with the chain in iptables mode. ([#85527](https://github.com/kubernetes/kubernetes/pull/85527), [@aojea](https://github.com/aojea))

* Kubernetes v1.13 moves support for Container Storage Interface to GA. As part of this move Kubernetes now supports CSI v1.0.0 and drops support for CSI 0.3 and older releases. Older CSI drivers must be updated to CSI 1.0 in order to work with Kubernetes 1.13+. ([#71020](https://github.com/kubernetes/kubernetes/pull/71020), [@saad-ali](https://github.com/saad-ali))

there are a few backwards-incompatible changes, most of which are rare use cases, bug fixes with side effects, or things that have been deprecated for multiple releases already:
  
  - https://github.com/kubernetes-sigs/kustomize/pull/4911: Drop support for a very old, legacy style of patches. patches used to be allowed to be used as an alias for patchesStrategicMerge in kustomize v3. You now have to use patchesStrategicMerge explicitly, or update to the new syntax supported by patches. See...

* Kubernetes version command line parameter in kubeadm has been updated to drop an unnecessary redirection from ci/latest.txt to ci-cross/latest.txt. Users should know exactly where the builds are stored on Google Cloud storage buckets from now on. For example for 1.9 and 1.10, users can specify ci/latest-1.9 and ci/latest-1.10...

* Kubernetes version command line parameter in kubeadm has been updated to drop an unnecessary redirection from ci/latest.txt to ci-cross/latest.txt. Users should know exactly where the builds are stored on Google Cloud storage buckets from now on. For example for 1.9 and 1.10, users can specify ci/latest-1.9 and ci/latest-1.10...

- Ensure the `KUBE-MARK-DROP` chain in kube-proxy IPVS mode. The chain is ensured for both IPv4 and IPv6 in dual-stack operation. ([#82214](https://github.com/kubernetes/kubernetes/pull/82214), [@uablrek](https://github.com/uablrek))

with to go1.18, which introduced significant changes to its garbage collection algorithm. As a result, we observed an increase in memory usage for kube-apiserver in larger an heavily loaded clusters up to ~25% (with the benefit of API call latencies drop by up to 10x on 99th percentiles). If the memory increase is not acceptable for you you can mitigate by setting GOGC env variable (for our tests using GOGC=63 brings memory usage back to original value, although the exact value may depend on usage...