- Changed Job controller to use the controller UID index for Pod lookups to improve performance. ([#132305](https://github.com/kubernetes/kubernetes/pull/132305), [@xigang](https://github.com/xigang))

- Kubeadm: during execution of the "check expiration" command, treat the etcd CA as external if there is a missing etcd CA key file (etcd/ca.key) and perform the proper validation on certificates signed by the etcd CA. Additionally, make sure that the CA for all entries in the output table is included - for both certificates...

- Resolves an issue that causes winkernel proxier to treat stale VIPs as valid ([#113567](https://github.com/kubernetes/kubernetes/pull/113567), [@daschott](https://github.com/daschott)) [SIG Network and Windows]

- Resolves an issue that causes winkernel proxier to treat stale VIPs as valid ([#113558](https://github.com/kubernetes/kubernetes/pull/113558), [@daschott](https://github.com/daschott)) [SIG Network and Windows]

- Kubeadm: during execution of the "check expiration" command, treat the etcd CA as external if there is a missing etcd CA key file (etcd/ca.key) and perform the proper validation on certificates signed by the etcd CA. Additionally, make sure that the CA for all entries in the output table is included - for both certificates...

- kubeadm: fix a potential panic if kubeadm discovers an invalid, existing kubeconfig file ([#79165](https://github.com/kubernetes/kubernetes/pull/79165), [@neolit123](https://github.com/neolit123))
- kubeadm: treat non-fatal errors as warnings when doing reset ([#80862](https://github.com/kubernetes/kubernetes/pull/80862), [@drpaneas](https://github.com/drpaneas))

- Kubeadm: during execution of the "check expiration" command, treat the etcd CA as external if there is a missing etcd CA key file (etcd/ca.key) and perform the proper validation on certificates signed by the etcd CA. Additionally, make sure that the CA for all entries in the output table is included - for both certificates...

- Resolved an issue that caused winkernel proxier to treat stale VIPs as valid. ([#113521](https://github.com/kubernetes/kubernetes/pull/113521), [@daschott](https://github.com/daschott))

can now store only `null` when created using the protobuf content-type or stored in etcd using protobuf serialization (the default in 1.6).
JSON API clients should tolerate `null` values for such fields, and treat `null` and `[]` as equivalent in meaning unless specifically documented otherwise for a particular field. ([#44593](https://github.com/kubernetes/kubernetes/pull/44593))

### Other notable changes