The users who signed up for the Kubernetes Desktop beta are being emailed by batches to make sure we control the quality at first. If you registered, you will receive an email in the coming weeks.
Kubernetes powered Docker for Mac 17.12 is now GA and is available for all. It brings experimental Kubernetes and the latest versions of Docker compose and Docker Machine. Irrespective of registered Beta programme, now you should be able to update your D4M. Please note that Docker for Windows will be the next target and release is around Feb 2018. For Linux, you might need to wait for another 2-3 months.