- Validation rules for Custom Resource Definitions can be written in the [CEL expression language](https://github.com/google/cel-spec) using the `x-kubernetes-validations` extension in OpenAPIv3 schemas (alpha). This is gated by the alpha "CustomResourceValidationExpressions" feature gate. ([#1...

- Fixed a regression in `1.27.0` that resulted in `missing metadata in converted object` errors when modifying objects for multi-version custom resource definitions with a conversion strategy of `None`. ([#117301](https://github.com/kubernetes/kubernetes/pull/117301), [@ncdc](https://github.com/ncdc))

## Changes by Kind

### Bug or Regression

- Fixes a regression in 1.27.0 that resulted in "missing metadata in converted object" errors when modifying objects for multi-version custom resource definitions with a conversion strategy of `None`. ([#117305](https://github.com/kubernetes/kubernetes/pull/117305), [@ncdc](https://github.com/ncdc)) [SIG API Machinery]

Kubernetes 1.11, you must keep the following in mind:

* **JSON configuration files that contain fields with incorrect case will no longer be valid. You must correct these files before upgrading.** When specifying keys in JSON resource definitions during direct API server communication, the keys are case-sensitive. A bug introduced in Kubernetes 1.8 caused the API server to accept a request with incorrect case and coerce it to correct case, but this behaviour has been fixed in 1.11 and the...

### Promoted Server Side Unknown Field Validation to Beta

- Kube-apiserver: openapi schemas published for custom resources now reference standard ListMeta schema definitions ([#92546](https://github.com/kubernetes/kubernetes/pull/92546), [@liggitt](https://github.com/liggitt)) [SIG API Machinery]

LICENSE_Apache Apache License Version 2.0, January 2004 http://www.apache.org/licenses/ TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION 1. Definitions. "License" shall mean the terms and conditions for use, reproduction, and distribution as defined by Sections 1 through 9 of this document. "Licensor" shall mean the copyright owner or entity authorized by the copyright owner that is granting the License. "Legal Entity" shall mean the union of the acting entity and all other entities...