Historical Rules · 23 January 2015
Rule 206.4
Official source text from the 23 January 2015 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 (WPN.Wizards.com/en/resources/rules-documents).