It is October and no announcement for module 18 has come. Module 17 added almost nothing to the game. Should I be worried?
Note that the only module announcement to come after September was module 2, back when there was a lot more staff and money in the game. Ever since then, the announcements came in August and September.
I can't imagine a module being released in the holiday season since support seems to drop heavily at that time.
Even if an announcement comes today we are looking at a November launch. I haven't even heard that people are alpha testing the new module yet.