Major bugs
Since the latest update there is a bug with how the resource cards are counted. Twice it has happened where I have enough resources to build but I get an error "insufficient resources." Playing against a friend in the same room we also noticed that the number of cards it shows the other players to have is not necessarily the true amount they have.
Also, in an online game I had exactly one grain, one ore, and one wool. I tried to buy a development card and nothing happened, again I tried and nothing happened. Finally after clicking a third time I ended up with 3 dev cards!
Costag23 about
Catan Classic, v4.6.1