Horizon Zero Dawn was released for PS4 in February 2017 before making the jump to PC in August 2020.
Former Guerrilla managing director Hulst previously claimed in February 2019 that the title had reached 10 million sales.
The updated sales figure means Horizon Zero Dawn is one of PlayStation’s best-selling games ever.
God of War, which released for PS4 in April 2018 and last month for PC, had sold 19.5 million copies as of August 2021, according to the platform holder. Spider-Man for PS4 has also reportedly sold over 20 million units.
Friday’s update was delivered one week ahead of the release of the game’s sequel, Horizon Forbidden West, on February 18.
This week, Guerrilla released the first footage of the game running on the base PS4, with one clip showing protagonist Aloy fighting a Tremortusk.
Sony also updated the PlayStation Store page for the PS4 version of Horizon Forbidden West to make it clearer that buyers are eligible to a free PS5 upgrade.
Prior to the sequel’s announcement, VGC exclusively reported that Sony was planning a trilogy of Horizon games.
The title is being developed by Guerrilla in partnership with new PlayStation studio Firesprite.