According to developers Sony seems to be working on an improved version of the PlayStation 4. The updated model would get more GPU and processor power to be ablt to deal with 4K and VR.
Since the updated model would allow the PlayStation 4.5 to work with VR and Ultra HD it remains unclear if the upgrade will be an update based on software tweaks, or if it'll be completely new hardware. Since Ultra HD is 4x more pixels opposed to 1080P this however in our opinion really would require some new hardware unless they dumb down on image quality significantly.
Obviously the PlayStation 4.5 is a temporary placeholder name as Sony definitely would not use that naming. One developer jokingly called it the ‘PS4K’ talking about the device. The PS4’s price dropped from $400 to $350 last fall, and one source indicated that this new ‘PS4.5’ could let Sony keep selling PS4 hardware at a higher profit margin for $400.