Boss Mick McCarthy has confirmed the exits of midfielders Lee Martin and Andy Drury and keeper Arran Lee-Barrett and that striker Michael Chopra and midfielder Jay Emmanuel-Thomas have been made available for transfer.
McCarthy told the club site: "Lee, Andy and Arran are all out of contract and have been released. I want to look at other options but we wish them every success for the future.
"I have also spoken to Michael Chopra and Jay Emmanuel-Thomas and told them that I don’t see them as being part of my plans going forward and they are free to look for another club.”
Town have also confirmed that keeper Jason Brown, who joined on a short-term contract in March, will not be extending his time at Portman Road.