This will be an all-new Elantra, and while we don't have any more details as of this writing, we might have already seen the new sedan in leaked, Korean-spec form. Just last month, Indian Autos Blog posted this photo of what's said to be the 2016 Elantra, scheduled to make its debut in South Korea in the near future. And since Hyundai has a habit of debuting its new cars in Korea before bringing them to the US, there's a chance this new sedan might be destined for our shores.
Of course, that's all speculation at this point. We'll know more later this year, likely before the new Elantra's official unveiling in Los Angeles this November.