20. Migration and Adoption Strategy
This section defines how the architecture is adopted pragmatically, without forcing wholesale replacement of existing systems or operating models.
20.1 Incremental Adoption
Adoption occurs incrementally and capability by capability.
Key characteristics:
- New capabilities are built using the target architecture
- Existing capabilities are migrated only when there is clear value
- Multiple architectural styles may coexist temporarily
Incremental adoption:
- Reduces upfront risk
- Preserves delivery momentum
- Allows teams to build confidence progressively
This avoids “big bang” transformations.
20.2 Coexistence with Existing Platforms
Existing platforms continue to operate during migration.
Coexistence is achieved through:
- Clear integration boundaries
- Encapsulation of legacy behaviour behind capabilities
- Avoidance of invasive refactoring
Principles:
- Legacy systems are treated as dependencies, not foundations
- New capabilities do not inherit legacy constraints by default
- Coexistence is intentional, not accidental
This enables gradual transition without service disruption.
20.3 Decommissioning Legacy Patterns
Legacy patterns are retired deliberately.
Decommissioning is driven by:
- Reduced dependency through capability substitution
- Measurable decline in usage
- Clear ownership and retirement plans
Practices include:
- Parallel run periods
- Explicit end-of-life milestones
- Removal of unused integrations and contracts
This prevents long-term architectural drift.
20.4 Success Metrics
Success is measured through outcomes, not activity.
Metrics include:
- Time to deliver new capabilities
- Reduction in integration complexity
- Operational stability and incident rates
- Cost predictability across deterministic and AI workloads
Success metrics:
- Are reviewed regularly
- Inform further migration decisions
- Drive continuous improvement
This ensures adoption delivers sustained value.