- 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...

- Added a `kubernetes_feature_enabled` metric which will tell you if a feature is enabled. ([#112652](https://github.com/kubernetes/kubernetes/pull/112652), [@logicalhan](https://github.com/logicalhan))

    * Custom apiservers built with the latest apiserver library will have the 100MB limit on the body of resource requests as well. The limit can be altered via ServerRunOptions.MaxRequestBodyBytes.
    * The body size limit does not apply to subresources like pods/proxy that proxy request content to another server.

- 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

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.