Received summons for a 18 year old case what problems can we face

a case of 18 years back of kidnapping was reopened and we were called for wittness from the court how it can be. As we have filed the case at that time and till date nothing happened and suddenly we are getting a notice after 18 years just pls tell me hw such an old case can be reopened after sucha long period. we have got a notice from court on the top its written summon to witness. Is there any issue or any problem we have to face according to the notice.