History of CR 207.2a

Every distinct wording since 2010, newest first.

May 3, 2019 · War of the Spark
Reminder text is italicized text within parentheses that summarizes a rule that applies to that card. It usually appears on the same line as the ability it’s relevant to, but it may appear on its own line if it applies to an aspect of the card other than an ability.
January 25, 2019 · Ravnica Allegiance
Reminder text is italicized text within parentheses that summarizes a rule that applies to that card. It usually appears on the same line as the ability it's relevant to, but it may appear on its own line if it applies to an aspect of the card other than an ability.
February 1, 2014 · Born of the Gods
Reminder text is italicized text within parentheses that summarizes a rule that applies to that card. It usually appears on the same line as the ability it’s relevant to, but it may appear on its own line if it applies to an aspect of the card other than an ability.
September 30, 2011 · Innistrad
Reminder text is italicized text within parentheses that summarizes a rule that applies to that card. It usually appears on the same line as the ability it's relevant to, but it may appear on its own line if it applies to an aspect of the card other than an ability.
June 17, 2011 · Commander 2011
The card may have a characteristic-defining ability that sets its power and/or toughness
April 1, 2011 · Duel Decks: Knights vs. Dragons
The card may have a characteristic-defining ability that sets its power and/or toughness according to some stated condition. (See rule 604.3.) Such an ability is worded "[This creature's] [power or toughness] is equal to . . ." or "[This creature's] power and toughness are each equal to . . ." This ability functions everywhere, even outside the game. If the ability needs to use a number that can't be determined, including inside a calculation, use 0 instead of that number.
February 4, 2011 · Mirrodin Besieged
The card may have a characteristic-defining ability that sets its power and/or toughness according to some stated condition. (See rule 604.3.) Such an ability is worded “[This creature’s] [power or toughness] is equal to . . .” or “[This creature’s] power and toughness are each equal to . . .” This ability functions everywhere, even outside the game. If the ability needs to use a number that can’t be determined, including inside a calculation, use 0 instead of that number.
October 1, 2010 · Scars of Mirrodin
The card may have a characteristic-defining ability that sets its power and/or toughness
February 1, 2010 · Worldwake
The card may have a characteristic-defining ability that sets its power and/or toughness according to some stated condition. (See rule 604.3.) Such an ability is worded "[This creature's] [power or toughness] is equal to . . ." or "[This creature's] power and toughness are each equal to . . ." This ability functions everywhere, even outside the game. If the ability needs to use a number that can't be determined, use 0 instead of that number.