Apparently it's not optional... it shows upcoming events, however Apple has defined them. I had an event scheduled last night, and it showed on the notification screen... later, after the event was over I looked at the screen and it was gone... nothing there today... and my next calendar event is still +27 hours and change away from now... maybe it's a 24 hour preview?
I think it's a 24 hour preview, I played with it throughout the night and decided to head back to 4.3.3 and sit out until beta 3 ... Battery still seems the same as Beta 1 for me which is hard because I am not near a power source most of the day. Overall though a nice improvement to the best beta they have ever put out.
