- The endpointslice mirroring controller mirrors endpoints annotations and labels to the generated endpoint slices, it also ensures that updates on any of these fields on the endpoints are mirrored. 
  The well-known annotation endpoints.kubernetes.io/last-change-trigger-time is skipped and not mirrored. ([#100443](https://github.com/kubernetes/kubernetes/pull/100443), [@aojea](https://github.com/aojea)) [SIG Apps, Network and Testing]

		// if peers already exist and for one of them ReplicateILMExpiry
		// set true, that means earlier replication of ILM expiry was set
		// for the site replication. All new sites added to the setup should
		// get this enabled as well
		if replicateILMExpirySet {
			peerReplicateILMExpiry = replicateILMExpirySet
		} else {
			peerReplicateILMExpiry = opts.ReplicateILMExpiry
		}
		joinReq.Peers[v.DeploymentID] = madmin.PeerInfo{

It upgrades the version of Starlette to `0.15.0`, now based on [AnyIO](https://anyio.readthedocs.io/en/stable/), and the internal async components in **FastAPI** are now based on AnyIO as well, making it compatible with both **asyncio** and **Trio**.

You can read the docs about running [FastAPI with Trio using Hypercorn](https://fastapi.tiangolo.com/deployment/manually/#hypercorn-with-trio).

- The apiserver debug endpoint `/debug/api_priority_and_fairness/dump_requests` has been extended to dump executing requests as well as queued ones.  A column for StartTime has been added to the returned table, with the queued requests having a StartTime of "0001-01-01T00:00:00Z".  The executing requests have a RequestIndexInQueue of -1, and the QueueIndex is also -1 for priority...

                                type: string
                              metric:
                                description: |-
                                  One of the well-known [Istio Standard Metrics](https://istio.io/latest/docs/reference/config/metrics/).

- Using `--log-file` is known to be problematic in 1.15. This presents as things being logged multiple times to the same file. The behaviour and details of this issue, as well as some preliminary attempts at fixing it are documented [here](https://github.com/kubernetes/kubernetes/issues/78734#issuecomment-501372131)

## Urgent Upgrade Notes

Subject to the terms and conditions of this License, each Contributor hereby grants to You a perpetual, worldwide, non-exclusive, no-charge, royalty-free, irrevocable (except as stated in this section) patent license to make, have made, use, offer to sell, sell, import, and otherwise transfer the Work, where such license applies only to those patent claims licensable by such Contributor that are necessarily infringed by their Contribution(s) alone or by combination of their Contribution(s) with the Work...

A security issue was discovered in kube-apiserver that could allow an attacker controlled aggregated API server to redirect client traffic to any URL.  This could lead to the client performing unexpected actions as well as leaking the client's credentials to third parties.