Is it permissible for the buyer to accept an item of better or lesser quality than the one stipulated in the Salam contract upon maturity?
Chapter on Guaranteed Salaf (Advance Payment) for a Specified Term
Al-Mughni
Book of Sales
Primary text
If the buyer accepts something of the same genus but superior or inferior in characteristics to the stipulated item, it is permissible because this is not considered a sale; rather, it is the settlement of a debt with a favor from one of the parties.