Early sale copies of Lala have revealed that season four of Natsume Yujincho will premiere in January of 2012. Season three of the series will end next week in Japan. The title of season four will be 夏目友人帳 肆 (Natsume Yujincho Shi). More details will be revealed in future issues.
Most are attributing this to the new seasons being a "split two cours series," a series that is originally planned to be two seasons with a break between the seasons. Other series that had this format were The World God Only Knows (Kaminomizo Shiru Sekai) and Sekaiichi Hatsukoi.