This deposit presents the updated foundational hypothesis and Phase 1 validation design of the Lattice-Field Medium (LFM) — a deterministic lattice model proposing that relativity, gravitation, quantization, and cosmological expansion all emerge from a single discrete field law. LFM treats spacetime as a lattice of interacting energy cells governed by the canonical equation∂²E/∂t² = c²∇²E − χ(x,t)²E, with c² = α/β. In the continuum limit, this relation reproduces the variable-mass Klein–Gordon equation, yielding Lorentz symmetry, inertial behavior, and quantized energy exchange as emergent phenomena. Version 2.0 supersedes the initial Conceptual Hypothesis Release. It incorporates refined formulations, explicit continuum-limit definitions, updated test-design tolerances, and a complete reproducibility architecture. Numerical Tier 1–3 validation data will follow in future proof-packet releases. Included materials:• LFM Master v2.0 — conceptual framework and interpretation• LFM Core Equations v1.1 — canonical PDE and discrete update law• LFM Phase 1 Test Design v2.1 — validation architecture and workflow• LFM Test Plan.xlsx — tier criteria, tolerances, and seed data• Executive Summary v3.0 — overview of results and next-phase objectives• README_LFM.txt — package summary and directory map This version establishes Phase 1 reproducibility and theoretical coherence across all LFM documents while maintaining the canonical field equation unchanged.All content is distributed under CC BY-NC 4.0 International (non-commercial use with attribution).