Inheritance division when a man divorces one of four wives, marries a fifth, and the one divorced is unknown.
Chapter on Distant Kindred (Dhawu al-Arham)
Al-Mughni
Book of Inheritance Shares (Farā'id)
Primary text
If a man has four wives, divorces one, marries a fifth, and dies without specifying whom he divorced, the fifth wife inherits one-fourth (rub'), and the remaining three-fourths are divided among the four remaining wives.
Supporting text
This is the school of thought of Abu Hanifa, provided the fifth marriage occurred after the waiting period ('idda) of the divorced woman ended. If the husband stated, 'One of my wives is divorced,' after marrying the fifth, and subsequently married a sixth, dying before clarifying, the sixth inherits one-fourth, the fifth inherits one-fourth of the remaining three-fourths, and the balance is divided among the initial four wives.