OtOpcUa-side requirements all met or trivially met by v2: Basic256Sha256 + SignAndEncrypt + username token (transport security covers this), reject-and-trust cert workflow, endpoint URL must NOT include /discovery suffix (forum-documented failure mode), hostname-stable certs (decision #86 already enforces this since clients pin trust to ApplicationUri), OI Gateway service must NOT run under SYSTEM (deployment-guide concern). Two integrator-burden risks tracked: validation/GxP paperwork (no AVEVA blueprint exists for non-AVEVA upstream servers in Part 11 deployments — engage QA/regulatory in Year 1) and unpublished scale benchmarks (in-house benchmark required in Year 2 before cutover scheduling).
Phase 1 acceptance gains Task E.10 (decision #142): end-to-end AppServer-via-OI-Gateway smoke test against a Phase 1 OtOpcUa instance, catching AppServer-specific quirks (cert exchange, endpoint URL handling, service account, security mode combo) well before the Year 3 tier-3 cutover schedule. Non-blocking for Phase 1 exit if it surfaces only documentation-level fixes; blocking if it surfaces architectural incompatibility.
New file `docs/v2/aveva-system-platform-io-research.md` captures the full research with all source citations (AVEVA docs, Communications Drivers Pack readmes, Software Toolbox / InSource partner walkthroughs, Inductive Automation forum failure-mode reports). Plan.md decision log gains #141 and #142; Reference Documents section links the new doc.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
