What you mean by update? 1.8A was released a week ago with all the new content and is on the main page. If you mean the bugfix patch 1.8B that will be a couple of days to a week or two when the developer has fixed all the main bugs.
It's been Christmas since the main release so imagine some time was taken off work. Now it is just a matter of how long the bugs take to fix, could be days, could be weeks....
