- The v1 Endpoints API is now officially deprecated (though still fully supported). The API will not be removed, but all users should use the EndpointSlice API instead. ([#130098](https://github.com/kubernetes/kubernetes/pull/130098), [@danwinship](https://github.com/danwinship)) [SIG API Machinery and Network]

- Fixed a bug to prevent segmentation fault from occurring when updating deeply nested JSON fields. ([#134381](https://github.com/kubernetes/kubernetes/pull/134381), [@kon-angelo](https://github.com/kon-angelo)) [SIG API Machinery and CLI]

          <name>groupId</name>
          <version>3.0.0+</version>
          <required>true</required>
          <description>
            A universally unique identifier for a project. It is normal to
            use a fully-qualified package name to distinguish it from other
            projects with a similar name (eg. {@code org.apache.maven}).
          </description>
          <type>String</type>
        </field>
        <field>

  
    - When using Services with SessionAffinity, client affinity for an
      endpoint now gets broken when that endpoint becomes non-ready
      (rather than continuing until the endpoint is fully deleted).
  
    - Traffic to a service IP now starts getting rejected (as opposed to
      merely dropped) as soon as there are no longer any *usable*
      endpoints, rather than waiting until all of the terminating

- Fixed attaching volumes after detach errors. Now volumes that failed to detach are not treated as attached. Kubernetes will make sure they are fully attached before they can be used by pods. ([#120595](https://github.com/kubernetes/kubernetes/pull/120595), [@jsafrane](https://github.com/jsafrane))

* Fix issue in Portworx volume driver causing controller manager to crash ([#76341](https://github.com/kubernetes/kubernetes/pull/76341), [@harsh-px](https://github.com/harsh-px))
* Fixes segmentation fault issue with Protobuf library when log entries are deeply nested. ([#77224](https://github.com/kubernetes/kubernetes/pull/77224), [@qingling128](https://github.com/qingling128))

- Fully removed `PostStartHookContext.StopCh`. ([#127341](https://github.com/kubernetes/kubernetes/pull/127341), [@mjudeikis](https://github.com/mjudeikis))

- Fixed attaching volumes after detach errors. Now volumes that failed to detach are not treated as attached, Kubernetes will make sure they are fully attached before they can be used by pods. ([#120595](https://github.com/kubernetes/kubernetes/pull/120595), [@jsafrane](https://github.com/jsafrane)) [SIG Apps and Storage]

## Changelog since v1.18.19

## Changes by Kind

### Bug or Regression

- Reverted the previous fix for portforward cleanup because it introduced a kubelet regression which can lead into segmentation faults. ([#102838](https://github.com/kubernetes/kubernetes/pull/102838), [@saschagrunert](https://github.com/saschagrunert)) [SIG API Machinery and Node]

## Dependencies

### Added
_Nothing has changed._

- To enhance usability and developer experience, CRD validation rules now support direct use of (CEL) reserved keywords as field names in object validation expressions for existing expressions in storage, will fully support runtime in next release for compatibility concern. ([#126188](https://github.com/kubernetes/kubernetes/pull/126188), [@cici37](https://github.com/cici37)) [SIG API Machinery and Testing]