Warning, one more time - Castling is *not* possible.
The position is the same as standard chess, and all the other rules are the same also, but normal openings will be changed by this difference.



Update
Something went wrong, and castling is possible. Players will not be "kicked out" of the event for it.
In my games, I will stay with the theme - I pledge not to castle, but expect opponents to do it. Because the server IS allowing it, players will NOT be punished for doing it.
I don't know why
This was set up with a FEN (position notation) that did NOT include legal castling. Somehow that got changed. I will open a support ticket, but probably (almost surely) it can't be fixed now that games have already started. I am sorry that it is not what you expected, but I don't know why it happened. At least the games are unrated...