- Fixed bugs in handling of server-side apply, create, and update API requests for objects containing duplicate items in keyed lists.
  - A `create` or `update` API request with duplicate items in a keyed list no longer wipes out managedFields. Examples include env var entries with the same name, or port entries with the same containerPort in a pod spec.

## Changelog since v1.17.6

## Changes by Kind

### API Change

- Resolve regression in metadata.managedFields handling in update/patch requests submitted by older API clients ([#92008](https://github.com/kubernetes/kubernetes/pull/92008), [@apelisse](https://github.com/apelisse)) [SIG API Machinery and Testing]

### Feature

- The kube-apiserver now resets `managedFields` that got corrupted by a mutating admission controller. ([#98074](https://github.com/kubernetes/kubernetes/pull/98074), [@kwiesmueller](https://github.com/kwiesmueller))

## Changelog since v1.18.3

## Changes by Kind

### API Change

- Resolve regression in metadata.managedFields handling in update/patch requests submitted by older API clients ([#92007](https://github.com/kubernetes/kubernetes/pull/92007), [@apelisse](https://github.com/apelisse)) [SIG API Machinery and Testing]

### Feature

## Changelog since v1.16.10

## Changes by Kind

### API Change

- Resolve regression in metadata.managedFields handling in update/patch requests submitted by older API clients ([#91748](https://github.com/kubernetes/kubernetes/pull/91748), [@apelisse](https://github.com/apelisse)) [SIG API Machinery and Testing]

### Feature

- Improved memory usage of kube-apiserver by dropping`.metadata.managedFields` field that self-requested informers of kube-apiserver didn't need. ([#124667](https://github.com/kubernetes/kubernetes/pull/124667), [@linxiulei](https://github.com/linxiulei)) [SIG API Machinery]

- Describing the CRs will now hide `.metadata.managedFields` ([#114584](https://github.com/kubernetes/kubernetes/pull/114584), [@soltysh](https://github.com/soltysh))

- Made usage of key encipherment optional in API validation. ([#111061](https://github.com/kubernetes/kubernetes/pull/111061), [@pacoxu](https://github.com/pacoxu))
- ManagedFields time is correctly updated when the value of a managed field is modified. ([#110058](https://github.com/kubernetes/kubernetes/pull/110058), [@glebiller](https://github.com/glebiller))
- OpenAPI will no longer duplicate these schemas:

- Apiserver: used the correct error when logging errors updating managedFields. ([#113711](https://github.com/kubernetes/kubernetes/pull/113711), [@andrewsykim](https://github.com/andrewsykim))