Historical Rules · 1 February 2014
Rule 206.4
Official source text from the 1 February 2014 Rules release
Players may include cards from any printing in their constructed decks if those cards appear in sets allowed in that format (or those cards are specifically allowed by the _Magic_ Tournament Rules). See the _Magic_ Tournament Rules for the current definitions of the constructed formats (<Wizards.com/WPN/Events/Rules.aspx>).