It can still be optional to run higher octane. Older Volvo 5 cylinders could run 87 with no problem because they only ran 9lbs of boost (only certain models). Most modern turboed engines usually can optionally run more boost if you put in higher octane. The issue is they rely on detection of early detonation when running worse fuel. Which scares me because of it fails engine goes boom very fast.
Use the octane that is recommended for your vehicle.