- Fixed an issue with stuck connections handling error responses ([#71412](https://github.com/kubernetes/kubernetes/pull/71412), [@liggitt](https://github.com/liggitt))
- apiserver: fixed handling and logging of panics in REST handlers ([#71076](https://github.com/kubernetes/kubernetes/pull/71076), [@liggitt](https://github.com/liggitt))

* kube-apiserver: requests to endpoints handled by unavailable extension API servers (as indicated by an `Available` condition of `false` in the registered APIService) now return `503` errors instead of `404` errors. ([#58070](https://github.com/kubernetes/kubernetes/pull/58070), [@weekface](https://github.com/weekface))

- 'Container `preStop` and `postStart` lifecycle handlers using `httpGet` now
  honor the specified `scheme` and `headers` fields. This enables setting custom
  headers and changing the scheme to `HTTPS`, consistent with container
  startup/readiness/liveness probe capabilities. Lifecycle handlers configured
  with `scheme: HTTPS` that encounter errors indicating the endpoint is actually

- The `baseline` and `restricted` pod security admission levels blocked setting the `host` field on probe and lifecycle handlers. ([#125271](https://github.com/kubernetes/kubernetes/pull/125271), [@tssurya](https://github.com/tssurya)) [SIG Auth, Node and Testing]

### Other notable changes

### Bug or Regression

- Adds node event handlers to dual stack kube-proxy implementation to fix Topology Aware Hints. ([#101054](https://github.com/kubernetes/kubernetes/pull/101054), [@robscott](https://github.com/robscott)) [SIG Network]

* Fix a scheduler panic due to internal cache inconsistency ([#71063](https://github.com/kubernetes/kubernetes/pull/71063), [@Huang-Wei](https://github.com/Huang-Wei))
* apiserver: fixes handling and logging of panics in REST handlers to prevent crashes ([#71076](https://github.com/kubernetes/kubernetes/pull/71076), [@liggitt](https://github.com/liggitt))

### Bug or Regression

- Fix missing delete events on informer re-lists to ensure all delete events are correctly emitted and using the latest known object state, so that all event handlers and stores always reflect the actual apiserver state as best as possible ([#115900](https://github.com/kubernetes/kubernetes/pull/115900), [@odinuge](https://github.com/odinuge)) [SIG API Machinery]

### Bug or Regression

- Fix missing delete events on informer re-lists to ensure all delete events are correctly emitted and using the latest known object state, so that all event handlers and stores always reflect the actual apiserver state as best as possible ([#115901](https://github.com/kubernetes/kubernetes/pull/115901), [@odinuge](https://github.com/odinuge)) [SIG API Machinery]

- The 404 request handler for the GCE Ingress load balancer now exports prometheus metrics, including:

  - `http_404_request_total` (the number of 404 requests handled)
  - `http_404_request_duration_ms` (the amount of time the server took to respond in ms)