- An end-user may choose to request logs without confirming the identity of the backing kubelet.  This feature can be disabled by setting the `AllowInsecureBackendProxy` feature-gate to false. ([#83419](https://github.com/kubernetes/kubernetes/pull/83419), [@deads2k](https://github.com/deads2k))

- E2e framework: the `node-role.kubernetes.io/master` taint has been removed from the default value of `--non-blocking-taints` flag. You may need to set `--non-blocking-taints` explicitly if the cluster to be tested has nodes with the deprecated `node-role.kubernetes.io/master` taint. ([#118510](https://github.com/kubernetes/kubernetes/pull/118510), [@SataQiu](https://github.com/SataQiu))...

- Kube-apiserver: Added support for disabling caching of authorization webhook decisions in the `--authorization-config` file. The new fields `cacheAuthorizedRequests` and `cacheUnauthorizedRequests` could be set to `false` to prevent caching for authorized or unauthorized requests. See the https://kubernetes.io/docs/reference/access-authn-authz/authorization/#using-configuration-file-for-authorization...

- Fixes regression in logging spurious stack traces when proxied connections are closed by the backend ([#82588](https://github.com/kubernetes/kubernetes/pull/82588), [@liggitt](https://github.com/liggitt))
- RateLimiter add a context-aware method, fix client-go request goruntine backlog in async timeout scene. ([#79375](https://github.com/kubernetes/kubernetes/pull/79375), [@answer1991](https://github.com/answer1991))

### **Instrumentation**

#### **Audit**

*   Adjust batching audit webhook default parameters: increase queue size, batch size, and initial backoff. Add throttling to the batching audit webhook. Default rate limit is 10 QPS. ([#53417](https://github.com/kubernetes/kubernetes/pull/53417),[ @crassirostris](https://github.com/crassirostris))

* Log audit backend can now be configured to perform batching before writing events to disk. ([#60237](https://github.com/kubernetes/kubernetes/pull/60237), [@crassirostris](https://github.com/crassirostris))

Before upgrading to Kubernetes 1.13, you must keep the following in mind:

- kube-apiserver

* Ensure the backend pools are set correctly for Azure SLB with multiple backend pools (e.g. outbound rules) ([#76691](https://github.com/kubernetes/kubernetes/pull/76691), [@feiskyer](https://github.com/feiskyer))

* Add --request-timeout to kube-apiserver to make global request timeout configurable. ([#51415](https://github.com/kubernetes/kubernetes/pull/51415), [@jpbetz](https://github.com/jpbetz))
* Fix for Nodes in vSphere lacking an InternalIP. ([#48760](https://github.com/kubernetes/kubernetes/pull/48760)) ([#49202](https://github.com/kubernetes/kubernetes/pull/49202), [@cbonte](https://github.com/cbonte))

    * [fluentd-gcp addon] Bump prometheus-to-sd to v0.5.0 to pick up security fixes.
    * [metatada-proxy addon] Bump prometheus-to-sd v0.5.0 to pick up security fixes.
* Ensure the backend pools are set correctly for Azure SLB with multiple backend pools (e.g. outbound rules) ([#76691](https://github.com/kubernetes/kubernetes/pull/76691), [@feiskyer](https://github.com/feiskyer))