- kube-proxy: a configuration file specified via `--config` is now loaded with strict deserialization, which fails if the config file contains duplicate or unknown fields. This protects against accidentally running with config files that are malformed, mis-indented, or have typos in field names, and getting unexpected behavior. ([...

- Custom resource requests with `fieldValidation=Strict` consistently require `apiVersion` and `kind`, matching non-strict requests ([#109019](https://github.com/kubernetes/kubernetes/pull/109019), [@liggitt](https://github.com/liggitt))

- Added a new option `strict-cpu-reservation` for CPU Manager static policy. When this option is enabled, CPU cores in `reservedSystemCPUs` will be strictly used for system daemons and interrupt processing no longer available for any workload. ([#130290](https://github.com/k...

- The getters for the field name and typeDescription of the Reflector struct were renamed. ([#128035](https://github.com/kubernetes/kubernetes/pull/128035), [@alexanderstephan](https://github.com/alexanderstephan)) [SIG API Machinery]

- Kubernetes is now built using go 1.17. ([#103692](https://github.com/kubernetes/kubernetes/pull/103692), [@justaugustus](https://github.com/justaugustus))
- Performs strict server side schema validation requests via the `fieldValidation=[Strict,Warn,Ignore]`. ([#105916](https://github.com/kubernetes/kubernetes/pull/105916), [@kevindelgado](https://github.com/kevindelgado))
- Promote `IPv6DualStack` feature to stable.

* [IPVS] Allow for transparent kube-proxy restarts ([#75283](https://github.com/kubernetes/kubernetes/pull/75283), [@lbernail](https://github.com/lbernail))

- Moved the CPU Manager static policy option `strict-cpu-reservation` to the GA version. ([#134388](https://github.com/kubernetes/k...

- Changed how the API server handles updates to `.spec.defaultBackend` of Ingress objects.

- Promoted meta.k8s.io/v1beta1 Table and PartialObjectMetadata to v1. ([#77136](https://github.com/kubernetes/kubernetes/pull/77136), [@smarterclayton](https://github.com/smarterclayton))

- Adds the ability to pass --strict-transport-security-directives to the kube-apiserver to set the HSTS header appropriately.  Be sure you understand the consequences to browsers before setting this field. ([#96502](https://github.com/kubernetes/kubernetes/pull/96502), [@249043822]...