More details are to be revealed soon, as this news are a kind of a tease. However, we know for sure that the upcoming update will have improvements to matchmaking, a new stage, and a new Rage Quit system apart from the addition of Guile. Check out this developer blog to know more about the character as well a new stage that he brings into the game. There you will find info on the character overview and detailed description of his skills.
Sonic Boom!