First a pachinko site mentioned it. Now Sony Computer Entertainment Japan is talking about Persona 5 even though Atlus hasn’t announced the title yet.
The possible leak comes from a creator interview found on Sony’s mobile PlayStation page. The interview is actually about Shin Megami Tensei: Persona, the PSP version, but the top page lists Meguro as the producer of Persona 5.
I suppose this could be an innocent typo. Even if it is Persona is the most popular MegaTen branch, which means a sequel is a no brainer. Persona 5 is a sure bet just like Final Fantasy XV. Whether Meguro is the producer or not is another story.