- Drop additional rule requirement (cronjobs/finalizers) in the roles who use kubectl create cronjobs to be backwards compatible ([#124883](https://github.com/kubernetes/kubernetes/pull/124883), [@ardaguclu](https://github.com/ardaguclu)) [SIG CLI]

- Fixed the ability to set the `resolvConf` option in drop-in kubelet configuration files, which validates that drop-in kubelet configuration files are in a supported version. ([#127421](https://github.com/kubernetes/kubernetes/pull/127421), [@liggitt](https://github.com/liggitt))

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...

- Drop support for the deprecated and unsupported kubectl run flags:
  - filename
  - force
  - grace-period
  - kustomize
  - recursive
  - timeout
  - wait
  

- 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))

* 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))

* 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

### Bug or Regression

- Drop additional rule requirement (cronjobs/finalizers) in the roles who use kubectl create cronjobs to be backwards compatible ([#124883](https://github.com/kubernetes/kubernetes/pull/124883), [@ardaguclu](https://github.com/ardaguclu)) [SIG CLI]

- 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...