http://gematsu.com/2017/01/final-fantasy-xv-total-shipments-top-six-million
Note: this meaning an additional one million units were shipped is Gematsu's speculation (not mentioned in the press release). It's more likely IMO that the extra 1 million since launch day is a combination of shipments and digital sales.Total shipments and digital sales for Final Fantasy XV have exceeded six million units, Square Enix announced.
That means an additional one million units were shipped since the game's first day shipments of five million.