Oracle Changes
There are a few cards which are receiving errata to their Oracle text with the release of this set. You can find the official text of any card on Gatherer.
Zevlor, Elturel Exile
Zevlor's activated ability was inadvertently printed without the word "only," which made the "single target" requirements read very oddly. This has been added in the Oracle card reference.
Old text:
Haste
{o2}, {oT}: When you next cast an instant or sorcery spell that targets a single opponent or a single permanent an opponent controls this turn, for each other opponent, choose that player or a permanent they control, copy that spell, and the copy targets the chosen player or permanent.
New text:
Haste
{o2}, {oT}: When you next cast an instant or sorcery spell that targets only a single opponent or a single permanent an opponent controls this turn, for each other opponent, choose that player or a permanent they control, copy that spell, and the copy targets the chosen player or permanent.
Neera, Wild Mage
Neera, Wild Mage's printed text wasn't quite clear about what happens to the nonland card you revealed if you choose not to cast it. The text has received an update to clarify that it goes to the bottom of your library with the other cards.
Old text:
Whenever you cast a spell, you may put it on the bottom of its owner's library. If you do, reveal cards from the top of your library until you reveal a nonland card. You may cast that card without paying its mana cost. Then put the rest on the bottom of your library in a random order. This ability triggers only once each turn.
New text:
Whenever you cast a spell, you may put it on the bottom of its owner's library. If you do, reveal cards from the top of your library until you reveal a nonland card. You may cast that card without paying its mana cost. Then put all revealed cards not cast this way on the bottom of your library in a random order. This ability triggers only once each turn.
Dynaheir, Invoker Adept
Dynaheir has an ability that, once activated, will copy the next ability you activate if you spent at least four mana to activate it. However, the card was printed without the words that are normally on this kind of ability that stop mana abilities from causing it to trigger. Without those words, activating a mana ability by spending four or more mana does cause it to trigger, but, contrary to what you might expect, that mana ability isn't copied when the triggered ability resolves.
"What?"
Yeah, it's weird. Mana abilities, by design, work very differently from other kinds of abilities. The biggest difference is that, to prevent them from being responded to, mana abilities don't use the stack; their effects happen immediately after they are activated. This difference comes with some odd implications for copy effects. A copy effect looks at the object in the game it is trying to copy, usually a permanent on the battlefield or a spell or ability on the stack, and uses that object as a template to determine what the copy should look like. In technical rules terms, we call this template an object's "copiable characteristics." Because a mana ability resolves immediately after being activated, it doesn't create an object that has these copiable characteristics. Without a template to build from, a copy effect trying to copy a mana ability won't do anything at all.
Are you still with me after that? It's admittedly a bit of a brain-twister. To sum up, we've added the missing words to Dynaheir's Oracle text so that the trigger condition will ignore mana abilities entirely.
Old text:
Haste
You may activate abilities of other creatures you control as though those creatures had haste.
{T}: When you next activate an ability this turn by spending four or more mana to activate it, copy that ability. You may choose new targets for the copy.
New text:
Haste
You may activate abilities of other creatures you control as though those creatures had haste.
{T}: When you next activate an ability that isn't a mana ability this turn by spending four or more mana to activate it, copy that ability. You may choose new targets for the copy.
Introduction
Comprehensive Rules Changes
Oracle Changes