Hawthorn.1 is the first release on the "H" line of Open edX releases, and it is available now.
The docs have been updated, including Hawthorn release notes. Installation on Ubuntu is the same as with previous releases. Devstack is now based on Docker rather than Virtualbox. Start here to understand your options.
Thanks to all who helped test the Hawthorn beta and release candidates. It went very smoothly, and your feedback was invaluable. I'm sorry that we had a year-long gap between Ginkgo and Hawthorn. We're aiming to get the next release (Ironwood!) out in less time.
As usual, if you need help with Hawthorn (or any Open edX release), the openedx-ops mailing list, or the #ops channel in Slack, are the best places to get help: http://open.edx.org/gett