I think it’s safe to conclude that Arnold won’t be in EX4. The tiny hope to see him in the movie was relying on the fact that he was going to be in Europe for the Arnold Sport event and then fly to Bulgaria to shoot a few scenes. Well he’s not even going to his own event and will be attending virtually! He’s injured his calf and the drs advised him against any travel.
Goodbye legend! It was good to have you in the first 3 movies. The franchise won’t be the same without you!