Every distinct wording since 2010, newest first.
April 22, 2021 · Strixhaven
Encore is an activated ability that functions while the card with encore is in a graveyard. “Encore [cost]” means “[Cost], Exile this card from your graveyard: For each opponent, create a token that’s a copy of this card that attacks that opponent this turn if able. The tokens gain haste. Sacrifice them at the beginning of the next end step. Activate only as a sorcery.”
February 5, 2021 · Kaldheim
A boast ability is a special kind of activated ability. “Boast — [Cost]: [Effect]” means “[Cost]: [Effect]. Activate this ability only if this creature attacked this turn and only once each turn.”