The Δ72 Coherence Operator and Conditional Deterministic Closure of Millennium Instability Classes Version 1.6 of this manuscript formalizes the Δ72 Coherence Operator as a coherence-bounded analytical framework capable of inducing conditional deterministic closure of instability classes underlying the Clay Millennium Problems. Rather than asserting universal or classical proofs, this work introduces Δ72 as a structured extension layer: a mathematically defined operator whose deterministic predictions hold only when explicit coherence assumptions are satisfied. The operator is equipped with a coherence invariant κκκ, discrepancy functional ΔdiscΔ_{\text{disc}}Δdisc, and harmonic closure functional HHH. Under bounded coherence and monotone discrepancy descent, Δ72 acts as a Banach-type contraction, collapsing trajectories toward a unique harmonic fixed point across diverse mathematical and physical domains. Version 1.6 includes expanded and refined content, such as:• A strengthened “Non-Claims” section specifying the conditional nature of all results• Revised SA1–SA5 structural assumptions governing coherence-bounded evolution• Updated discrepancy geometry and Δ72-entropy monotonicity proofs• Refinements to domain realizations of P vs NP, Navier–Stokes, Yang–Mills, RH, Hodge, BSD, and Poincaré• A unified deterministic-closure template demonstrating how Δ72 resolves instability classes• An expanded Falsifiability section including spin-glass transitions, photonic cavity drift suppression, tensor-field collapse, and enzyme-network coherence• A full Sovereign Ledger cross-verification architecture for documenting and validating Δ72 closures• Appendix D: enhanced Sovereign Canon extensions, including scroll physics, identity harmonics, and multi-life coherence structures This manuscript positions the Δ72 Operator as a conditional, empirically falsifiable, coherence-based framework. Its predictions apply to domains that admit stable coherence capacity, a finite discrepancy structure, and a nonempty harmonic manifold. In such domains, Δ72 provides deterministic closure where classical approaches face instability or ambiguity. This is the authoritative V1.6 release, incorporating all updated definitions, proofs, diagrams, and ledger integration.