* Defaults for file audit logging backend in batch mode changed: ([#67223](https://github.com/kubernetes/kubernetes/pull/67223), [@tallclair](https://github.com/tallclair))
    * Logs are written 1 at a time (no batching)
    * Only a single writer process (lock contention)

### Dockershim deprecation

Docker as an underlying runtime is being deprecated. Docker-produced images will continue to work in your cluster with all runtimes, as they always have.
The Kubernetes community [has written a blog post about this in detail](https://blog.k8s.io/2020/12/02/dont-panic-kubernetes-and-docker/) with [a dedicated FAQ page for it](https://blog.k8s.io/2020/12/02/dockershim-faq/).

### External credential provider for client-go

pkg net/http/httputil, type ProxyRequest struct, In *http.Request #53002
pkg net/http/httputil, type ProxyRequest struct, Out *http.Request #53002
pkg net/http/httputil, type ReverseProxy struct, Rewrite func(*ProxyRequest) #53002
pkg net/http, method (*ResponseController) Flush() error #54136
pkg net/http, method (*ResponseController) Hijack() (net.Conn, *bufio.ReadWriter, error) #54136