Although the detractors did not have any evidence, Sony’s recent moves may seem to be supporting. In connection with the recent disclosure of Sony’s patent, they recently applied for a patent on downward-compatible technology.
The latest patent for Sony's application was February 13, and the patented technology was 'backward compatibility testing of software in disturbed-time mode', which may mean that the PS5 console will be compatible with PS4, PS3, and even PSV games.
Many guess that this is for the PS5 to prepare, so PS5 development tools have not been laid to the developer is not impossible, if it is true, then this host may be on sale next year, we will wait and see.