I say, and with God's help: It is not required to wet both feet; rather, it is invalidated by wetting more than one of the feet or both with water after wiping over them; because it is not permissible to combine washing and wiping, and the ruling for the majority applies to all. See: Umdat al-Ri'ayah 1: 114, and Sharh al-Wiqayah p. 114.