Another of the many redecoes/minor remoulds of the Studio Series line will be filling the unknown spot of SS-31, with the SS-13 TF2 Megatron getting a slightly different paint job, and a new head (damaged after his battle with Optimus in Egypt at the end of the movie).
As with a few toys recently, this one just appeared on shelves without any warning or listing anywhere... being found in Hong Kong first at Hobbybase.