PS5 Confirmed to Be Backwards Compatible with PS4 Games - Push Square
Sony Confirms That PS5 Is Only Backwards Compatible With PS4 | Player.One
Full PS5 Backwards Compatibility with PS4, PS3, PS2, and PS1 Games Hinted At By Ubisoft - YouTube
Recently there's an influx of “PS5 backwards compatible” articles on google reporting it will play ps1 through ps4 titles. If it's true, much respect to Sony. : r/PS3
How realistic would it be for the PS5 to be backwards compatible with PS1- PS4? : r/PS5
PS5 backward compatibility: PS4 games list, USB external drive support - Polygon