The original Evektor brakes on the SportStar Plus should use DOT 4. However, some aircraft have been upgraded to the MATCO Brake System which uses 5056 Aviation Standard Brake Fluid.
Check the calipers to tell which brake system your plane is using. If the calipers are gray, then they are the the original Evektor brakes and should use DOT 4. If the calipers have a gold anodized finish and say “MATCO” then use the 5056 Aviation Standard Brake Fluid.