As mentioned in the linked blog post, they're using Hyper-V as their hypervisor on Windows (it's a direct counterpart to xhyve on OSX, except entirely built into the OS).

The Docker for Mac and Windows beta does not use VirtualBox on either platform.

> it's a direct counterpart to xhyve on OSX, except entirely built into the OS

xhyve on Mac OS X is a very thin wrapper around Hypervisor.framework which itself is "entirely built into the OS".

My original question was if you need to run a separate VM for every Docker configuration or you can run different application versions at the same time. For example, running Outlook 2010, 2013, and 2016 side by side.

You can run multiple containers on a single host (VM).

Docker for Windows relies on Hyper-V