@okcorralsaid is enpassant enforced here and if so how?
The server code recognizes when it is a legal move and allows it if it is played; if the move is not legal in the given position, then the server code recognizes this and it cannot be played.
En Passant is legal in RedHotPawn, but a situation in which you can use it is rare. If the pawn moves up 2, making it side-by-side with an enemy pawn, the enemy may take it as if it only moved up one.