- Previously, the pod name and namespace were eliminated in the event log message. This PR attempts to add the preemptor pod UID in the preemption event message logs for easier debugging and safer transparency. ([#119971](https://github.com/kubernetes/kubernetes/pull/119971), [@kwakubiney](https://github.com/kwakubiney)) [SIG Scheduling]

- Changed kubectl describe to compute age of an event using the `EventSeries.count` and `EventSeries.lastObservedTime`. ([#104482](https://github.com/kubernetes/kubernetes/pull/104482), [@harjas27](https://github.com/harjas27))

- Scheduler now registers event handlers dynamically. ([#101394](https://github.com/kubernetes/kubernetes/pull/101394), [@Huang-Wei](https://github.com/Huang-Wei)) [SIG Scheduling and Testing]

 - Fixed a 1.18 regression in wait.Forever that skips the backoff period on the first repeat ([#90476](https://github.com/kubernetes/kubernetes/pull/90476), [@zhan849](https://github.com/zhan849)) [SIG API Machinery]

* kubectl apply now supports explicitly clearing values not present in the config by setting them to null ([#40630](https://github.com/kubernetes/kubernetes/pull/40630), [@liggitt](https://github.com/liggitt))

* Fixed an issue with informers missing an `Added` event if a recently deleted object was immediately recreated at the same time the informer dropped a watch and relisted. ([#83911](https://github.com/kubernetes/kubernetes/pull/83911), [@matte21](https://github.com/matte21))

* Bump event-exporter to 0.2.2 to pick up security fixes. ([#66157](https://github.com/kubernetes/kubernetes/pull/66157), [@loburm](https://github.com/loburm))

* kubelet: Fix bug where `runAsUser: MustRunAsNonRoot` strategy didn't reject a pod with a non-numeric `USER`. ([#56708](https://github.com/kubernetes/kubernetes/pull/56708), [@php-coder](https://github.com/php-coder))
* Add iptables rules to allow Pod traffic even when default iptables policy is to reject. ([#52569](https://github.com/kubernetes/kubernetes/pull/52569), [@tmjd](https://github.com/tmjd))

### Other notable changes

* Connections from Pods to Services with 0 endpoints will now ICMP reject immediately, rather than blackhole and timeout. ([#72534](https://github.com/kubernetes/kubernetes/pull/72534), [@thockin](https://github.com/thockin))

    * [event-exporter addon] Bump event-exporter to 0.2.3 to pick up security fixes.
* PVC may not be synced to controller local cache in time if PV is bound by external PV binder (e.g. kube-scheduler), double check if PVC is not found to prevent reclaiming PV wrongly. ([#67062](https://github.com/kubernetes/kubernetes/pull/67062), [@cofyc](https://github.com/cofyc))