Maybe I missed it in the rule book, but how do you play with promo cards, or other cards from past sets, using the day/night mechanics in War of Shadows?
There is no set rule. Promo cards would simply not have a Day or Night effect, implicitly impacting the Day-Night balance in the Center Row.
You could "house rule" it, however: even-numbered cards are considered "Day", odd-numbered cards are considered "Night". There's really no right or wrong answer -- just have fun!