- Generate fake.NewClientset which replace the deprecated NewSimpleClientset, for kube-aggregator and sample-apiserver ([#136537](https://github.com/kubernetes/kubernetes/pull/136537), [@soltysh](https://github.com/soltysh)) [SIG API Machinery]

- Kube-aggregator: always sets unavailableGauge metric to reflect the current state of a service. ([#87778](https://github.com/kubernetes/kubernetes/pull/87778), [@p0lyn0mial](https://github.com/p0lyn0mial)) [SIG API Machinery]

- Fixed an issue that prevents the linking of trace spans for requests that are proxied through kube-aggregator. ([#124189](https://github.com/kubernetes/kubernetes/pull/124189), [@toddtreece](https://github.com/toddtreece))

- Replaced deprecated package `k8s.io/utils/pointer` with `k8s.io/utils/ptr` for the kube-aggregator apiregistration. ([#132701](https://github.com/kubernetes/kubernetes/pull/132701), [@PatrickLaabs](https://github.com/PatrickLaabs))

- Added port configuration to AuditSink webhook configuration service reference.
- Added port configuration to CRD Conversion webhook configuration service reference.
- Added port configuration to kube-aggregator service reference. ([#74855](https://github.com/kubernetes/kubernetes/pull/74855), [@mbohlool](https://github.com/mbohlool))

- Made `apiextensions-apiserver` binary linking static (also affects the deb and rpm packages). ([#114226](https://github.com/kubernetes/kubernetes/pull/114226), [@saschagrunert](https://github.com/saschagrunert))
- Made `kube-aggregator` binary linking static (also affects the deb and rpm packages). ([#114227](https://github.com/kubernetes/kubernetes/pull/114227), [@saschagrunert](https://github.com/saschagrunert))

- Make EBS volume expansion faster ([#66728](https://github.com/kubernetes/kubernetes/pull/66728), [@gnufied](https://github.com/gnufied))
- Remove unused binary and container image for kube-aggregator. The functionality is already integrated into the kube-apiserver. ([#67157](https://github.com/kubernetes/kubernetes/pull/67157), [@dims](https://github.com/dims))

- Kube-aggregator certificates are dynamically loaded on change from disk ([#92791](https://github.com/kubernetes/kubernetes/pull/92791), [@p0lyn0mial](https://github.com/p0lyn0mial)) [SIG API Machinery]

* Add aggregator_unavailable_apiservice_{count,gauge} metrics in the kube-aggregator. ([#71380](https://github.com/kubernetes/kubernetes/pull/71380), [@sttts](https://github.com/sttts))

- Kube-apiserver: redirect responses are no longer returned from backends by default. Set `--aggregator-reject-forwarding-redirect=false` to continue forwarding redirect responses. ([#112193](https://github.com/kubernetes/kubernetes/pull/112193), [@jindijamie](https://github.com/jindijamie)) [SIG API Machinery and Testing]