- All `klog` flags except for `-v` and `-vmodule` are deprecated. Support for `-vmodule` is only guaranteed for the text log format. ([#105042](https://github.com/kubernetes/kubernetes/pull/105042), [@pohly](https://github.com/pohly))

### Bug or Regression

- Added jitter factor to lease controller that better smears load on kube-apiserver over time. ([#101652](https://github.com/kubernetes/kubernetes/pull/101652), [@marseel](https://github.com/marseel)) [SIG API Machinery and Scalability]

- Service session affinity timeout tests are no longer required for Kubernetes network plugin conformance due to variations in existing implementations. New conformance tests will be developed to better express conformance in future releases. ([#112806](https://github.com/kubernetes/kubernetes/pull/112806), [@dcbw](https://github.com/dcbw)) [SIG Architecture, Network and Testing]

### SIG Scheduling

- We’re working to simplify the Windows node join experience with better scripts and kubeadm. Scripts and doc updates are still in the works, but some of the needed improvements are included in 1.15.  These include:

  * Fix the Kubelet PLEG update timestamp to better reflect the health of the component when the container runtime request hangs. ([#45496](https://github.com/kubernetes/kubernetes/pull/45496), [@andyxning](https://github.com/andyxning))

* fix network setup in hack/local-up-cluster.sh (https://github.com/kubernetes/kubernetes/pull/60431) ([#60633](https://github.com/kubernetes/kubernetes/pull/60633), [@pohly](https://github.com/pohly))
    * better error diagnostics in hack/local-up-cluster.sh output
* Add prometheus cluster monitoring addon to kube-up ([#62195](https://github.com/kubernetes/kubernetes/pull/62195), [@serathius](https://github.com/serathius))

interface could display a "Source" link that leads users to an archive
of the code.  There are many ways you could offer source, and different
solutions will be better for different programs; see section 13 for the
specific requirements.

  You should also get your employer (if you work as a programmer) or school,

* update QEMU version to v2.9.1 ([#50597](https://github.com/kubernetes/kubernetes/pull/50597), [@dixudx](https://github.com/dixudx))
* controllers backoff better in face of quota denial ([#49142](https://github.com/kubernetes/kubernetes/pull/49142), [@joelsmith](https://github.com/joelsmith))

- Implemented logging and event recording for probe results with an `Unknown` status in the kubelet's prober module. This helps in better diagnosing and monitoring cases where container probes return an `Unknown` result, improving the observability and reliability of health checks. ([#125901](https://github.com/kubernetes/kubernetes/pull/125901), [@jralmaraz](https://github.com/jralmaraz))...