Update (2016-04-23): Several minutes after the update to the official website was made, a new post was created indicating that the release date news was a fabrication by a third-party who hacked the website:
Old Post Based on Fake News
The Persona Channel—the official Atlus channel for Persona news—has been updated with a new news post announcing that Persona 5 will be released simultaneously for the PlayStation 4 and the PC on July 8, 2016, in Japan.
This news comes alongside the recent mystery countdown website launched for the game. The news post in question only mentions that the Persona 5 release date will be on July 8, 2016 for the PS4 and the PC, however the PlayStation 3 version of the game is not mentioned.
Persona 5 is slated to be released for the PS4 and PC in Japan on July 8, 2016, with a 2016 North American release date.