What do we currently know about backwards compatibility for the PlayStation 5 console? The ability to play is precisely limited to PS4 games, and it will be possible to play most games. In fact, this is all that Sony has officially declared.
A little bit of detail managed to extract the user Reddit thanks to viewing the source code of the site PlayStation Store. There were a few error messages and hints about compatibility.
For example, there is a warning saying that “while playing games for PS4 on PS5, some features available on PS4 may not be available”. Which ones, unfortunately, are not clear.
There is also the following message: “This game for PS4 is not supported by the current system software of your PS5. We continue to make more games for PS4 that you can play on PS5. Upgrade your PS5 and then try to play the game”. This indicates that a game for PS4 may not be available for PS5 at some point in time, but then the problem will be solved.
The message “PS5 boost mode enabled” hints that the new console will be able to improve games for the old one, as implemented in Xbox Series X/S, but no details are available. In addition, there is a mention of console sharing that allows you to use the same account on multiple consoles, giving all users of such consoles access to games on the main PS5.