Sonic Forces may not be out until November 7, 2017, but a mobile spin-off is already available. Sega has released Sonic Forces: Speed Battle on Apple iOS devices. This is a free-to-play endless runner with optional in-app purchases to get pocket money and extras.
Sonic Forces: Speed Battle lets people pick one of 15 playable characters and run through 12 tracks. Among the cast are Sonic, Tails, Knuckles, Amy, Shadow, Rouge, E-123 Omega, Metal Sonic, Charmy, Espio, Chaos, Vector, and Zavok, and you can collect rings as you run to improve them. There are three environments immediately available, two of which are taken from Sonic Forces. Naturally, there are also leaderboards.
An Android version of Sonic Forces: Speed Battle is also on the way. It will be released on November 16, 2017.