Just as their are Star Wars prequels there are the theoretical episodes in between episode VI and VII. This lends a new term besides prequels. After this new trilogy computers were be able to create "Middle Prequel Fill In Episodes to watch How the Force is Forgotten, and then "Awaken" 30 years later.
Episode 6&1/3 the Force Goes Vacation
Episode 6&1/2 Luke Screws Up Big Time
Episode 6&3/4 The Force Fall Asleep
Episode 6&7/8 Rise of 1st Order while the New Republic Bickers over Government Spending