Patterns / Application Architecture
Legacy Modernization
A decision framework across retain, re-host, re-platform, re-factor, re-purchase, and retire.
Portfolio
Scoring Model
Disposition
Roadmap
Decommission
Conceptual flow
Problem
Modernisation budgets are spent uniformly across a portfolio instead of where business value and risk concentrate.
Context
Large application estates where technical debt, licence cost, and capability overlap all compete for the same funding.
Solution
Score each application on business criticality, technical health, cost, and capability overlap; assign a disposition; sequence by dependency and risk.
Benefits
- Objective disposition decisions
- Portfolio-level sequencing
- Defensible investment case
Risks
- Stale portfolio data
- Political overrides of scoring
- Ignored integration fan-out
Trade-offs
- Analysis effort against decision quality
When to use
- Estates above ~100 applications
- Post-merger consolidation
- Cloud programme planning
When not to use
- Single-product organisations
- Greenfield builds
Related patterns
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