- Changed the error message to `cannot exec into multiple objects at a time` when file passed to `kubectl exec` contains multiple resources ([#114249](https://github.com/kubernetes/kubernetes/pull/114249), [@ardaguclu](https://github.com/ardaguclu))

- `kubectl run` can set a service account name in the generated pod
  spec with the `--serviceaccount` flag.

- `kubectl proxy` now correctly handles the `exec`, `attach`, and
  `portforward` commands.  You must pass `--disable-filter` to the command to allow these commands.

- Added `cronjobs.batch` to "all", so that `kubectl get all` returns them.

- Added `client-go` support for upgrading subresource fields from client-side to server-side management. ([#123484](https://github.com/kubernetes/kubernetes/pull/123484), [@erikgb](https://github.com/erikgb))
- Added `exec-interactive-mode` and `exec-provide-cluster-info` flags in kubectl config set-credentials command. ([#122023](https://github.com/kubernetes/kubernetes/pull/122023), [@ardaguclu](https://github.com/ardaguclu))

- Fixed a bug where the kubelet choose the wrong container by its name when running `kubectl exec`. ([#113041](https://github.com/kubernetes/kubernetes/pull/113041), [@saschagrunert](https://github.com/saschagrunert))