A new Sonic title will be released in 2017, presumably for current and next-generation platforms.
Sonic Team’s Takashi Iizuka revealed during a Sonic The Hedgehog 25th Anniversary party in Tokyo that a new Sonic game is in development and will be released in 2017. There is currently no information on what this title will be, however we are expected to see it on next-generation platforms such as the Xbox One, Playstation 4 and potentially the Nintendo NX.
Iizuka has confirmed that an official announcement will be live-streamed via Twitch on July 22nd, 2016, during the San Diego Comic Con.
Sonic’s next game Sonic Boom: Fire & Ice is scheduled to launch on September 27th, 2016.
Source: Gematsu.com