Iowa Code § 635.7
89 Acts, ch 25, §3; 2003 Acts, ch 151, § 57; 2004 Acts, ch 1120, §8; 2007 Acts, ch 134, §23, 28; 2012 Acts, ch 1123, §30; 2018 Acts, ch 1140, § 4, 6, 9 2018 amendment applies July 1, 2018, to estates of decedents dying on or after July 1, 2018; 2018 Acts, ch 1140, § 9