Blood_Tears on 16 September 2020
https://www.gamespot.com/articles/ps5-backwards-compatibility-99-of-ps4-games-will-be-playable-sony-boss-says/1100-6482283/
PS5 will be 99% BC with PS4.
"In an interview with The Washington Post, Sony Interactive Entertainment president and CEO Jim Ryan said that backwards compatibility has been tested with "thousands" of games, and that most of them work. In fact, the figure he gives is "99 percent," meaning that it will be rare for a PS4 game to not work on Sony's new console."
