Sony has recently shared an update on the launch timing for its next-generation console, PS5. They are also asking to wait before confirming full backward compatibility.
PS5 will be out in Fall 2020, Sony has confirmed it today. As far as the matter of backward compatibility is concerned, Sony wants to wait before giving an official confirmation on it.
In a statement given to Famitsu (via), the company shared the following update on the status of backward compatibility for PS5.
Currently, the dev team is putting all power on verifying whether they can secure a complete compatibility. Please wait for more information.
There have been patents published in the past that hinted at backward compatibility, at least for the legacy systems like PS4. It will be always hard to get 100% backward compatibility for PS5 so this might be just Sony being cautious around it.
As PS5 is launching next year, more information on the console should start to surface and we might get a clear picture when a full-blown reveal is planned for the console. Sony did confirm that their next console will be named PlayStation 5, so if you had any interest in knowing about the name of the next console, it should be clarified by now.