Beta 18 has been pushed to steam.
Always look at the bottom of the main menu to see if you are running the latest version. Steam auto updates, but can be slow about it sometimes.
Check the Beta Change Log for changes in this build.
https://knucklecracker.com/forums/index.php?topic=21323.0
Awesome, thanks for the hard work! Don't forget to sleep... after the release date. :P