Iowa Code § 902.6: Release.

A person who has been committed to the custody of the director of the Iowa department of corrections shall remain in custody until released by the order of the board of parole, in accordance with the law governing paroles, or by order of the judge after reconsideration of a felon’s sentence pursuant to section 902.4 or until the maximum term of the person’s confinement, as fixed by law, has been completed.