Update as the Minimal Dynamics of Reality

Canonical preprint manuscript. Paper 2 of 12 in Series A of the Theory of Difference / Information Update Physics (ToD/IUP) Foundational Physics Program. This paper follows Paper 1, “Difference as the First Physical Primitive” (DOI: 10.5281/zenodo.21025246), which established physical difference as the minimal condition for physical articulation and constructed physical states as quotient classes under consequence-based indistinguishability. Paper 2 asks the next structural question: once quotient-distinguishable physical states are available, what is the minimal form in which physical content becomes dynamically active? The answer proposed here is update. Update is not introduced as motion through space, evolution in an external time parameter, symbolic computation, transformation under an already completed law, or observation by a subject. At this layer, update means a physically admissible transition, preservation, selection, registration, coupling, or consequence relation by which quotient-surviving difference becomes active. The central claim is a necessity claim, not a sufficiency claim: physical dynamics requires at least one admissible non-null update, while difference alone opens only update potential. A symbolic arrow that produces no distinguishable quotient-level or witness-level consequence is dynamically null. The manuscript prepares the handoff to Paper 3 by showing how update chains, traces, composition, and order-sensitive consequences can ground pre-temporal update order without assuming time as a primitive container of change.