The last word in June 2016 was that StS would follow after the Santorini KS campaign (after StS was supposed to be a Q1 2016 release). Mindful that the Santorini campaign successfully funded and has a November 2016 delivery, there has been no word since and no sign of a KS campaign being launched.
I tested a late rules iteration a couple weeks ago with the designer an not to worry, the game is in the pipe but Roxley prefers to ensure mad levels of quality on each product it ships, so expect it to come once Santorini has run its course. It's going to be good.
Thanks for checking in - we love enthusiasm and don't mind queries at all!
Last I spoke with the designer and the Rooster in charge, the priority is indeed the delivery of Santorini, as Edward supposed. Next after that is Brass, and Sails To Steam is in line after that. Don't take this timeline as gospel (never take anything as gospel in this business), but we want the game in your hands just as much as you do... we just can't sacrifice quality or overcommit resources to make it happen sooner, so it's a slower process than we'd like sometimes.
As Dylan observed, playtesting continues in the meantime, so you can be sure the version that reaches your shelf will be very thoroughly polished.