Historical Rules · 25 August 2017
Rule 107.8a
Official source text from the 25 August 2017 Rules release
“{LEVEL N1-N2} [Abilities] [P/T]” means “As long as this creature has at least N1 level counters on it, but no more than N2 level counters on it, it has base power and toughness [P/T] and has [abilities].”