He is now Birmingham skipper and he has agreed an improved and extended contract with the Blues.
Carr's current deal was due to expire next summer.
But the 33-year-old has extended his stay via a 12-month option being added to the contract.
Carr was persuaded out of retirement by City boss Alex McLeish 18 months ago.
He has been one of Birmingham's most consistent performers and played a major role in them finishing ninth in the Barclays Premier League last season.