Updated with official details.
Reports of an enhanced next-gen port surfaced just a few weeks ago. "The PS4 version will also include the DLC so you will be able to play 'Left Behind' as well," Sony's Sercan Sulun said. In addition to the DLC, the Remastered Edition also includes "in-game cinematic commentary from the cast and creative director."
"Moving our efforts to the PS4 has allowed us to remaster an already phenomenal looking The Last of Us in 1080p with a list of upgrades including higher resolution character models, improved shadows and lighting, upgraded textures, along with even more improvements," Naughty Dog's Arne Myer confirmed on the PlayStation.Blog.