There is no max, but the costs grow exponentially. Atm you're not even limited by the sky and the dwarves can stack over the top of the screen, which will eventually have to be fixed. It will be technically and design-wise difficult task.
wich upgrades dont have an max? (i have the feeling that carying capacity dont have one) but are there any others?
No, all upgrades have a max. It's the dwarf units that don't.
thanks :) and this is a great game, i love that it gets updated so frequently
