And yes that page still says 3.6 because we like to wait a week or two after Joomla does an update to update our RocketLaunchers to the new Joomla version. It's because of issues like this, actually. Joomla has a habit of updating then releasing another update a few days later to fix bugs caused by the last update.
The number in the compaitiblity matrix is more about what comes included in the RocketLauncher. That update will come soon.
As of right now we're not seeing any problems at all if you are using one of our Gantry templates and want to upgrade Joomla to 3.7.