Is the subscription auto-renewing?

Does the subscription renew automatically each month or is it a manual pay? If it's automatic, how does one cancel?

Since it's an IAP, it's not automatic. If it is, it will have to ask you for your iTunes password every time.

It's not autorenew. If you log into the game after your time has expired you'll need to manually select the 'buy time' button and choose the amount of additional time you'd like to purchase.

And can you buy time before your time runs out? What I mean is, if you buy more time before the month is up, will it apply the next month automatically at the end of the month?

Yes, when you buy time it just adds it on to your existing subscription right then. So if your subscription expires say June 25 and today you buy another 30 days, your expiration date will change to July 25.

Say you run out of time but you are still in a game. When you buy some more time and come back after, say, a week: will you still be in the game? If so, will all your trade routes, harvesting routes, etc still be working while you weren't able to log on or is all production halted during the time you have no subscription?

I know you'll still be in the game, but not certain about the trade, harvesting and tech. Good question.

Yes, everything will be as you left it. When your subscription expires, nothing happens to your current games.

I just bought a year subscription. So keep up the good work, please :-D