Previously, for IPv6, if the podSubnet had a mask lower than /112, kubeadm calculated a node-mask to be multiple of eight and splitting the available bits to maximise the number used for nodes. ([#95723](https://github.com/kubernetes/kubernetes/pull/95723), [@aojea](https://github.com/aojea)) [SIG Cluster Lifecycle]

- Fixed a bug around restarting init containers in the right order relative to normal containers with `SidecarContainers` feature enabled. ([#120269](https://github.com/kubernetes/kubernetes/pull/120269), [@gjkim42](https://github.com/gjkim42))

- Overall, enable the feature of `PreferNominatedNode` will  improve the performance of scheduling where preemption might frequently happen, but in theory, enable the feature of `PreferNominatedNode`, the pod might not be scheduled to the best candidate node in the cluster. ([#93179](https://github.com/kubernetes/kubernetes/pull/93179), [@chendave](https://github.com/chendave)) [SIG Scheduling and Testing]

### Bug or Regression

### Bug or Regression

- Fixes a race condition in the iptables mode of kube-proxy in 1.27 and later
  that could result in some updates getting lost (e.g., when a service gets a
  new endpoint, the rules for the new endpoint might not be added until
  much later). ([#122757](https://github.com/kubernetes/kubernetes/pull/122757), [@hakman](https://github.com/hakman)) [SIG Network]

  which the scheduler might miss some updates for the Pods rejected by NodeUnschedulable plugin and put the Pods in the queue for a longer time than needed. ([#127427](https://github.com/kubernetes/kubernetes/pull/127427), [@sanposhiho](https://github.com/sanposhiho)) [SIG Scheduling]
- Fixes the bug in PodTopologySpread that only happens with QHint enabled, 

### Bug or Regression

- Fixes a race condition in the iptables mode of kube-proxy in 1.27 and later
  that could result in some updates getting lost (e.g., when a service gets a
  new endpoint, the rules for the new endpoint might not be added until
  much later). ([#122815](https://github.com/kubernetes/kubernetes/pull/122815), [@wedaly](https://github.com/wedaly)) [SIG Network]

For more information and for updates on resolution of this issue, see [#51899](https://github.com/kubernetes/kubernetes/issues/51899).

 - CSINode initialization does not crash kubelet on startup when APIServer is not reachable or kubelet has not the right credentials yet. ([#89589](https://github.com/kubernetes/kubernetes/pull/89589), [@jsafrane](https://github.com/jsafrane)) [SIG Storage]

* Pod priority and preemption is now enabled by default. Even if you don't plan to use this feature, you might need to take some action immediately after upgrading. In multi-tenant clusters where not all users are trusted, you are advised to create appropriate quotas for two default priority classes, system-cluster-critical and system-node-critical, which are...