- Removed generally available feature gate `LegacyServiceAccountTokenCleanUp`. ([#126839](https://github.com/kubernetes/kubernetes/pull/126839), [@carlory](https://github.com/carlory)) [SIG Auth]
- Removed generally available feature gate `MinDomainsInPodTopologySpread`. ([#126863](https://github.com/kubernetes/kubernetes/pull/126863), [@carlory](https://github.com/carlory)) [SIG Scheduling]

- Added `UserNamespacesPodSecurityStandards` feature gate to enable user namespace support for Pod Security Standards.
  Enabling this feature will modify all Pod Security Standard rules to allow setting: `spec[.*].securityContext.[runAsNonRoot,runAsUser]`.
  This feature gate should only be enabled if all nodes in the cluster support the user namespace feature and have it enabled.

- The `SidecarContainers` feature has graduated to GA. 'SidecarContainers' feature gate was locked to default value and will be removed in v1.36. If you were setting this feature gate explicitly, please remove it now. ([#129731](https://github.com/kubernetes/kubernetes/pull/129731), [@gjki...

## Urgent Upgrade Notes 

### (No, really, you MUST read this before you upgrade)

- 'The `IPv6DualStack` feature gate for external cloud providers was removed.
  (The feature became GA in 1.23 and the gate was removed for all other
  components several releases ago.) If you were still manually

- Added a new `FileKeyRef` field to containers, allowing them to load variables from files by setting this field.
  

- Enabled feature gates for PortForward (kubectl port-forward) over WebSockets by default (beta).
   - Server-side feature gate: PortForwardWebsocket
   - Client-side (kubectl) feature gate: PORT_FORWARD_WEBSOCKETS environment variable

- Feature gates for RemoteCommand (kubectl exec, cp, and attach) over WebSockets are now enabled by default (Beta).
  - Server-side feature gate: TranslateStreamCloseWebsocketRequests
  - Client-side (kubectl) feature gate: KUBECTL_REMOTE_COMMAND_WEBSOCKETS

- Marked the feature gate `ExperimentalHostUserNamespaceDefaulting` as deprecated.
  Enabling the feature gate already had no effect; the deprecation allows for removing the feature gate in a future release. ([#116723](https://github.com/kubernetes/kubernetes/pull/116723), [@SergeyKanzhelev](https://github.com/SergeyKanzhelev)) [SIG Node]

- The `EndpointSliceTerminatingCondition` feature gate was graduated to GA. The gate is now locked and will be removed in v1.28. ([#113351](https://github.com/kubernetes/kubernetes/pull/113351), [@andrewsykim](https://github.com/andrewsykim))
- `DynamicKubeletConfig` feature gate has been removed from the API server.
  Dynamic kubelet reconfiguration now can't be used even when older nodes are still

- Feature gate `CSIMigration` was locked to enabled. `CSIMigration` is GA now. The feature gate will be removed in `v1.27`. ([#110410](https://github.com/kubernetes/kubernetes/pull/110410), [@Jiawei0227](https://github.com/Jiawei0227))