Close-out
Phase 0 Readout
Architecture discovery synthesis and decision-readiness summary. This document consolidates findings, convictions, and recommendations for steering committee review.
Why this matters
This is the single document that determines whether Phase 1 mobilisation proceeds. It synthesises six weeks of architecture discovery into actionable recommendations.
What this informs
Steering committee funding decision, Phase 1 scope definition, vendor selection mandate, and the governance framework for transformation execution.
What remains unresolved
Three open decisions require steering committee input. Cost estimation blocked pending scenario lock. China regulatory timeline carries uncertainty.
Deliverables
0/9 confirmed
Avg Progress
37%
Open Decisions
3
Top Risks
3
Recommended Path
SCN-A
Current-state complexity exceeds initial assumptions
Eight systems across six domains with undocumented dependencies. Three legacy systems have no API layer — all integration is database-level or batch file transfer.
Integration brittleness is the primary technical risk
MuleSoft hub routes all dealer-to-backend communication. Tight coupling between Dealer Portal and SAP/Siebel creates cascade failure risk during any migration.
Legacy coupling limits pace of change
Siebel and Sitecore are intertwined with SAP at the data layer. No abstraction boundary exists. Any replacement must address all three simultaneously or build a façade.
Data ownership is undefined across domains
No canonical data model exists. Analytics pull from multiple uncoordinated sources with varying freshness. Cross-domain data contracts are implicit, not explicit.
China requires a distinct architecture track
PIPL compliance, ICP licensing, and GFW constraints make a configuration-overlay approach untenable. Shared domain models with independent infrastructure is the minimum viable approach.
Transformation is feasible but sequencing is critical
The composable approach is technically sound but requires disciplined phasing. Façade-first migration reduces risk. Attempting parallel workstreams without sequencing will create dependency conflicts.
Architecture Convictions
A composable, domain-driven architecture is the right structural foundation.
Vendor independence, regional flexibility, and pace-layered evolution outweigh the higher initial integration complexity. This is the only approach that accommodates China without architectural debt.
Migration must be incremental — façade-first, domain-by-domain.
Big-bang replacement carries unacceptable operational risk. The strangler-fig pattern with API façades allows validation at each stage and preserves rollback capability.
Observability is a precondition, not a follow-on.
A distributed architecture without comprehensive monitoring will be operationally fragile. Logging, tracing, and metrics must be present from day one of Phase 1.
Organisational alignment is as important as technical architecture.
Domain-driven boundaries require domain ownership. Dealer adoption requires field engagement. Both are organisational challenges, not technical ones.
Recommended Pathway
SCN-AComposable Best-of-Breed
Assemble from purpose-fit components
Replace legacy systems with a composable architecture using best-of-breed services for each domain. Headless CMS, independent service APIs, unified experience layer. Maximum flexibility, highest integration complexity.
Why this is the right path now
No vendor lock-in — swap any component independently
Pace-layered evolution — each domain moves at its own speed
Best capability per domain — not constrained by platform limits
What it optimises for
Long-term vendor independence and flexibility
Regional architecture divergence without debt
Pace-layered domain evolution
Tradeoffs accepted
Highest initial integration complexity
Requires strong API governance and contract management
More vendor relationships to manage
These decisions are open or under review and must be resolved before Phase 1 scope can be finalised.
Required validations
Current-state architecture map validated with all domain stakeholders
Capability maturity scores confirmed by domain owners
Scenario A integration complexity assessed via proof-of-concept
Unresolved dependencies
SAP upgrade roadmap confirmation from enterprise team
China CAC security assessment timeline (45–60 day lead time)
Enterprise architect availability for deviation review
Organisational alignment needs
Domain ownership mapped to reporting structure
Dealer network engagement model defined for Phase 1
Executive sponsorship confirmed for domain boundary changes
Architecture inputs still needed
Façade layer specification and technology selection
Observability stack decision (OpenTelemetry evaluation)
Cross-border data flow model for China operations
Overall Confidence
Discovery has established a credible evidence base. Confidence is contingent on scenario selection and three open decisions being resolved within the next two weeks.
Known Unknowns
China CAC assessment duration and outcome
SAP upgrade timeline and backward compatibility
Dealer network appetite for interface change
Top Risks
Façade layer isolates new components. Incremental migration with rollback capability at each stage. Integration test suite before each cutover.
Progressive rollout by region. Dealer feedback loop built into Phase 1. Training programme. Dual-interface period during transition.
Parallel China architecture track. Independent data storage. Legal review of all cross-border data flows. ICP licensing ahead of deployment.
Mitigation Posture
All critical risks have identified mitigations. Two require decisions before mitigations can be activated.
Current-State Truth
System inventory and architecture observations
Under reviewCapability Mapping
Business capability maturity assessment
DraftFuture-State Scenarios
Three pathways under evaluation
DraftRisk & Dependencies
Heatmap and dependency register
Decision neededDeprecation
Strangler-fig migration strategy
DraftChina Annex
Regulatory and infrastructure requirements
DraftEnterprise Alignment
Gold standard compliance report
In progressDecisions
Architecture decision records
In progressDeliverables
Phase 0 deliverable tracker
Close-out Statement
This phase has established a factual architecture baseline, evaluated future-state pathways, and created the decision conditions for mobilisation.
The discovery outputs are ready for steering committee review. Three architecture decisions require resolution before Phase 1 scope can be finalised. The recommended pathway — composable best-of-breed with strangler-fig migration — is supported by the evidence base documented across all nine deliverables.
Recommended Action
Schedule steering committee session to review findings, resolve open decisions, and approve Phase 1 scope.
Decision Window
Decisions required by end of April 2026 to maintain Phase 1 mobilisation timeline of May 2026.
Confidence
Medium-High. Evidence base is credible. Outstanding items are bounded and time-boxed.