Large Templating Changes

Mana Value

Moving forward, we will use the words "mana value" where we previously would have used the words "converted mana cost" on cards. Mana value means the same thing that converted mana cost meant previously. Just over 600 cards received errata to match, and it is not a functional change.

Shuffle

We've decided that when a card mentions a library and then instructs the same player to shuffle that library, we won't mention the library a second time. We issued errata to over 700 cards to follow suit. This is not a functional change.

Activation Restrictions

Some cards have activated abilities that you can only activate at certain times. Those cards had text such as "Activate this ability only any time you could cast a sorcery." Most of those cards have received errata to a shorter template, such as "Activate only as a sorcery." About 480 cards received the errata, and it is not a functional change.

Smaller Templating Changes

Can't attack planeswalkers

Some cards, such as Archangel of Tithes, prevent creatures from attacking planeswalkers. These cards previously said that creatures can't attack "you or a planeswalker you control." Due to this wording, there is some ambiguity around whether it applies to all planeswalkers you control or requires you to pick one. To make it clearer, they have now been given errata to say creatures can't attack "planeswalkers you control." It impacted seventeen cards and is not a functional change.

Enters or leaves the battlefield

Six creature cards have a triggered ability that triggers when that creature "enters the battlefield or leaves the battlefield." This phrase has been shortened to "enters or leaves the battlefield" on those cards. This is not a functional change.

Individual Card Updates

Elemental Expressionist

Elemental Expressionist went to print with an ability that triggered when "you exile" a creature from the battlefield. However, it isn't always clear to players who is exiling a permanent, especially when replacement effects get involved. To make it clearer how this effect is resolved, Elemental Expressionist has been given errata so that the ability triggers when the creature is put into exile instead. In most cases, this will have the same result. However, in cases where an opponent's spell or ability exiles the creature, such as is the case with Swords to Plowshares, it is a functional change.

Elemental Expressionist was:

Magecraft — Whenever you cast or copy an instant or sorcery spell, choose target creature you control. Until end of turn, it gains "If this creature would leave the battlefield, exile it instead of putting it anywhere else" and "When you exile this creature, create a 4/4 blue and red Elemental creature token."

New text:

Magecraft — Whenever you cast or copy an instant or sorcery spell, choose target creature you control. Until end of turn, it gains "If this creature would leave the battlefield, exile it instead of putting it anywhere else" and "When this creature is put into exile, create a 4/4 blue and red Elemental creature token."

Hofri Ghostforge

Hofri Ghostforge went to print with an ability that says it returns the exiled card to your graveyard. In some cases, however, the card might have been exiled from an opponent's graveyard to begin with, and we don't want it going back to a different graveyard. Technically, rule 400.3 already covers this, but we don't expect players to have to know that rule to play, so we're updating Hofri to clarify what it does.

Hofri Ghostforge was:

Spirits you control get +1/+1 and have trample and haste.
Whenever another nontoken creature you control dies, exile it. If you do, create a token that's a copy of that creature, except it's a Spirit in addition to its other types and it has "When this creature leaves the battlefield, return the exiled card to your graveyard."

New text:

Spirits you control get +1/+1 and have trample and haste.
Whenever another nontoken creature you control dies, exile it. If you do, create a token that's a copy of that creature, except it's a Spirit in addition to its other types and it has "When this creature leaves the battlefield, return the exiled card to its owner's graveyard."

Zaffai, Thunder Conductor

The wrong card name was inadvertently included in Zaffai's printed rules text. The Oracle text correctly reflects that the full name of the card is Zaffai, Thunder Conductor.

Zaffai, Thunder Conductor was:
Magecraft — Whenever you cast or copy an instant or sorcery spell, scry 1. If that spell's mana value is 5 or greater, create a 4/4 blue and red Elemental creature token. If that spell's mana value is 10 or greater, Zaffai, Thunder Collector deals 10 damage to an opponent chosen at random.

New text:

Magecraft — Whenever you cast or copy an instant or sorcery spell, scry 1. If that spell's mana value is 5 or greater, create a 4/4 blue and red Elemental creature token. If that spell's mana value is 10 or greater, Zaffai, Thunder Conductor deals 10 damage to an opponent chosen at random.

Muzzio, Visionary Architect

Muzzio, Visionary Architect previously required you to reveal a card to everyone and then, once they were done looking at it, put it onto the battlefield. Revealing a card you are about to put into a public zone is an extra unnecessary step, and that step has been removed. This is technically a functional change, but it should play exactly the same way.

Muzzio, Visionary Architect was:

{3}{U}, {T}: Look at the top X cards of your library, where X is the highest converted mana cost among artifacts you control. You may reveal an artifact card from among them and put it onto the battlefield. Put the rest on the bottom of your library in any order.

New text:

{3}{U}, {T}: Look at the top X cards of your library, where X is the highest mana value among artifacts you control. You may put an artifact card from among them onto the battlefield. Put the rest on the bottom of your library in any order.

Ashling's Prerogative

Ashling's Prerogative referred to "converted mana cost of the chosen value," which would become "mana value of the chosen value." That's a little too much value, so we're calling the odd or even choice a quality instead. A similar change was also applied to Extinction Event and Lavabrink Venturer.

Ashling's Prerogative was:

As Ashling's Prerogative enters the battlefield, choose odd or even. (Zero is even.)
Each creature with converted mana cost of the chosen value has haste.
Each creature without converted mana cost of the chosen value enters the battlefield tapped.

New text:

As Ashling's Prerogative enters the battlefield, choose odd or even. (Zero is even.)
Each creature with mana value of the chosen quality has haste.
Each creature without mana value of the chosen quality enters the battlefield tapped.

Blood Scrivener

Added the word "you" in two places to make it a little more explicit who is doing the actions.

Blood Scrivener was:

If you would draw a card while you have no cards in hand, instead draw two cards and lose 1 life.

New text:

If you would draw a card while you have no cards in hand, instead you draw two cards and you lose 1 life.

Introduction
Comprehensive Rules Changes
Oracle Changes