The Official Japanese Sonic Twitter/X has announced that the game's first major patch is available for download leading up to the game's launch. They recommend applying this patch before starting to play.
While we don't have details on what's in the patch, it likely contains stability fixes much like most Day-1 patches.
And as a reminder, Sonic Superstars officially releases tomorrow... in a couple of hours. So whatever platform you've chosen, prepare for a preliminary download.