Centre-half Elkan Baggott has joined Championship Millwall on a permanent deal.
We understand the fee could rise to £2.25 million after add-ons with Town having a 20 per cent of profit sell-on.
The 23-year-old came through the Blues academy and went on to make seven senior starts and two sub appearances, scoring once.
Born in Bangkok and raised in Colchester, Baggott won 28 full international caps with Indonesia while with the club, scoring twice, and was the first player from that nation to play in the EFL.
While with the Blues, he spent time on loan at King’s Lynn, Gillingham, Cheltenham Town, Bristol Rovers and Blackpool.
"I’m delighted to bring Elkan to the club,” Steve Gallen, Millwall’s director of football, told his club’s official site.
"He’s a player we’ve been tracking for some time now and we’ve followed his development closely - both at Ipswich Town and through his loan spells in the EFL, where he has picked up valuable experience against senior, physical opposition.
"He’s a good age, has a real appetite to improve and fits the profile we look for defensively.
"Elkan comes in to bolster our defensive options in an area that has been a real strength for us in recent seasons and we’re confident he’ll add real competition and quality to that group.
"We’re pleased he’s chosen to join and we’re looking forward to seeing him progress here.”