Historical Rules · 27 September 2013
Rule 206.4
Official source text from the 27 September 2013 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).