Forum:Reprinted rulings

i have a question what happens if you're in a duel and you have two of the same cards one of them is the erected (older) version and the other is the new reprinted version do the rules state that you have to go by whatever the most recent rulings for a card is or does it not matter? to be more specific i have a grave keeper deck and i have 2 different necrovalleys the first one (which is the older one) negates all the effects of cards that involve graveyards whereas my other one simply says it negates the effects of cards that target cards in either players graveyard and then there is the one from structure deck marik which is the latest one that states cards in either player's graveyard cannot be affected by card effects.except for their own effects. so out of these three does it matter which one i have in my deck or does it not matter because all of them whether old or not have to follow the ruling of the latest reprinted version?