## Changelog since v1.23.15

## Changes by Kind

### API Change

- Kubernetes 1.23 is now built with go1.19.4. To match behavior of previous Kubernetes 1.23 patch releases:
  - `kube-apiserver` defaults the GOGC setting to 63, to approximate go1.17 garbage collection memory performance in heavily loaded API servers

    - [Server Binaries](#server-binaries-6)
    - [Node Binaries](#node-binaries-6)
  - [Changelog since v1.12.3](#changelog-since-v1123)
    - [Action Required](#action-required)
    - [Other notable changes](#other-notable-changes-6)
- [v1.12.3](#v1123)
  - [Downloads for v1.12.3](#downloads-for-v1123)
    - [Client Binaries](#client-binaries-7)
    - [Server Binaries](#server-binaries-7)

- Fixed a regression in 1.23 that incorrectly pruned data from array items of a custom resource that set `x-kubernetes-preserve-unknown-fields: true`. ([#107688](https://github.com/kubernetes/kubernetes/pull/107688), [@liggitt](https://github.com/liggitt))

- Allowed setting the `hostnameOverride` field in `PodSpec` to specify any RFC 1123 DNS subdomain as the pod's hostname. The `HostnameOverride` feature gate was introduced to control enablement of this functionality. ([#132558](https://github.com/kubernetes/kubernetes/pull/132558), [@HirazawaUi](https://github.com/HirazawaUi)) [SIG...

- github.com/google/cadvisor: [v0.44.1 → v0.45.0](https://github.com/google/cadvisor/compare/v0.44.1...v0.45.0)
- github.com/google/cel-go: [v0.12.3 → v0.12.4](https://github.com/google/cel-go/compare/v0.12.3...v0.12.4)
- github.com/imdario/mergo: [v0.3.5 → v0.3.6](https://github.com/imdario/mergo/compare/v0.3.5...v0.3.6)

- Modify DNS-1123 error messages to indicate that RFC 1123 is not followed exactly ([#94182](https://github.com/kubernetes/kubernetes/pull/94182), [@mattfenwick](https://github.com/mattfenwick)) [SIG API Machinery, Apps, Auth, Network and Node]

- Scheduler's assumed...

- cloud.google.com/go/vpcaccess: v1.7.1 → v1.7.4
- cloud.google.com/go/webrisk: v1.9.1 → v1.9.4
- cloud.google.com/go/websecurityscanner: v1.6.1 → v1.6.4
- cloud.google.com/go/workflows: v1.11.1 → v1.12.3
- cloud.google.com/go: v0.110.7 → v0.112.0
- github.com/Azure/go-ansiterm: [d185dfc → 306776e](https://github.com/Azure/go-ansiterm/compare/d185dfc...306776e)

## 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

* Restored the pre-1.10 behavior of the openstack cloud provider, which uses the instance name as the Kubernetes Node name. This requires instances be named with RFC-1123 compatible names. ([#63903](https://github.com/kubernetes/kubernetes/pull/63903), [@liggitt](https://github.com/liggitt))