2014-04-26 : Heroic abilities will resolve before the spell that caused them to trigger.

2014-04-26 : Heroic abilities will trigger only once per spell, even if that spell targets the creature with the heroic ability multiple times.

2014-04-26 : Heroic abilities won't trigger when a copy of a spell is created on the stack or when a spell's targets are changed to include a creature with a heroic ability.

2018-12-07 : If a card in a player's graveyard has {X} in its mana cost, X is considered to be 0.