This picture was found in Sonic Stadium's Twitter. From what it's said, Japan will probably be getting the TV series. Since 2015 is already here, this is probably the time for the other countries to get the Tv series as well. But here's one small thing.
Remember the spin off in Japan was called Sonic Toon? Well the Tv series for Japan will remain as Sonic Boom instead of Toon. Why they changed the title is unknown. When more information comes, I'll put it in here.
A little reminder, Boom will continue on January 17th in America, and from other news posts, The Middle East and the Guilli Network will get it in Spring this year, while Europe and everyone else will get it on Fall this year.