There are some core messages that use the most significant bit of a card code to store other information when creating a message for clients, for example, MSG_DRAW adds a flag to check if the card was drawn in face-up position. When cards with id above that number are used, the game will exhibit weird behavior where messages use the bit.
There are some core messages that use the most significant bit of a card code to store other information when creating a message for clients, for example, MSG_DRAW adds a flag to check if the card was drawn in face-up position. When cards with id above that number are used, the game will exhibit weird behavior where messages use the bit.