Paul Caddis is the latest player to sign a new contract, following both Demarai Gray and Clayton Donaldson.
The defender, whose original deal ran until next summer, has signed a one-year extension that will keep him at the club until at least June 2017.
Joining on loan from Swindon in August 2012 Caddis has gone on to make 119 appearances for the club.
A year’s option is available so he could remain at Blues until 2018 making that 5 years at the club in total.
By scoring the stoppage time goal that kept Blues in the Championship in 2014, he became an instant hero.
Finishing last season with the captains armband, the Scott has cemented his place on the right flank.