Players that already own the game will still have access to it and mods on the Steam version of the game will not be affected.
The Sonic X Shadow Generations game will launch on October 25 for PlayStation 5, PlayStation 4, Xbox Series X|S, Xbox One, Nintendo Switch, and PC via Steam and the Epic Games Store. Those who pre-order the game will receive the Sonic Adventure Legacy Skin. Those who order the Digital Deluxe Edition will be able to play the game three days early on October 22.
The game is a new collection of iconic 2D and 3D Sonic levels from Sonic Generations, remastered and expanded. The game also includes a new standalone campaign for players to take on the role of Shadow the Hedgehog.
Sonic Generations was originally released for the PlayStation 3 and Xbox 360 in 2011 to commemorate the 20th anniversary of the series. Sega later released the tor PC and 3DS.
Source: Sonic the Hedgehog franchise's X/Twitter account via Siliconera