O'Donoghue, Edge and Regis extend stayCharley and Chris haven't made their first team bow yet but have impressed enough at U21s level to stay another year, having both come into the club twelve months ago.
He has battled back from knee surgery this season and his performances in recent U21s matches have earned him a new contract.
Having come through the age groups at the U's, Michael made his first team debut at Barnsley in 2014/15 but has been restricted since by serious injury.
U21s regulars Michael O'Donoghue, Charley Edge and Chris Regis all put pen to paper on one year deals earlier this week.
Three of the U's youngsters have signed new contracts ahead of next season.