A general update rule for Choquet preferences is proposed and characterized. The update rule includes the major update rules such as the Dempster-Shafer rule (Shafer, 1976) and the Dempster-Fagin-Halpern rule (Dempster, 1967; Fagin and Halpern, 1991) as special cases. The axiomatic basis is established through a consistent counterfactual mapping that bridges between unconditional and conditional preferences. For any act, the mapping necessarily takes the form of a trinary act consisting of the minimum, maximum, and conditional certainty equivalent outcomes in the range of every act. The nature of the update rule is examined from the perspective of belief-by-belief updates.
