In the know about (5)

(Other definitions for upon that I've seen before include "Onto" , "Children's tales may begin ` `Once .... a time' '" , "Straddling" , "Immediately after" , ".... my word! I'm shocked" .)

(Other definitions for onto that I've seen before include "forward, with a destination" , "(Moving) aboard" , "To a place on" , "In contact with - aware of" , "To the whole of (maths.)" .)