A stop order has been accepted into the trading engine. Once triggered, it will go through other normal events starting with "new".
An order has generated a fill, both on maker and taker sides. Will be the first change event sent if an order matches on execution.
An order is canceled by the user.
LIMIT FOK orders with no fill, LIMIT IOC or MARKET orders that partially fill, GTT orders past time.
An order without a stop has been accepted into the trading engine. Will not be sent as a discrete change event if the order matches on execution.