According to a question and answer page, it will not be possible to enjoy this functionality with your PS3, PS2 and the first PlayStation titles.
Life is a dream, as the title of the famous play by Calderón de la Barca, which does not mean that waking up from that trance does not suppose a jug of cold water, especially for all those who still hope that PlayStation 5 be backward compatible with all previous Sony consoles. When the Japanese announced that their next-generation machine would be able to enjoy PS4 games, everything seemed to indicate that the system would not work with the previous platforms, a suspicion that Ubisoft has just confirmed, at least as regards their games.
In a question and answer page, the French company has explained how it will be the process of transferring video games from PS4 to the next generation machine. At the bottom of the message, however, it is clarified that this will not be possible for all video games in the PlayStation family. “Backward compatibility will work with supported PlayStation 4 titles, but will not be possible for PlayStation 3, PlayStation 2 and PlayStation video games.”