An unknown Tesla Model S unit with a larger charging port and slightly different taillights and trim elements can be seen in two admittedly grainy leaked pictures, which have triggered speculations about possible upgrades coming to the electric flagship sedan.
https://www.notebookcheck.net/Leaked-pictures-of-an-alleged-Tesla-Model-S-prototype-hint-at-possible-charging-port-and-taillight-upgrades.586336.0.html