Backward compatibility will be one of the core features of the next generation, which is why Sony and Microsoft are working hard to do this in the best possible way.
While the implementation at Microsoft is probably a little easier and has been taken into account for a long time, this is a bit more complicated at PlayStation in order to ensure full downward compatibility.
Remastering engine?
According to current reports, a remastering engine is to be used here, which covers everything from the PSone to the PS4. In addition, this should also ensure that the games do not just run, but are also upgraded. 4K resolution, a higher frame rate, etc. would be conceivable here.
However, it is currently not possible to finally confirm whether this information is correct, as there are no official statements to date on this. The only thing that is clear is that backward compatibility is an important feature of the next generation.
The PS5 is expected to premiere in the course of the next few weeks, probably in February.
"