Estate
2M LOC
Shipment management at multi-million-line scale — too large for spreadsheet parity between legacy and new.
HC3 logistics case
You cannot sunset what you cannot prove is covered.
A logistics company’s shipment management estate — 2M lines of code. Continuous enhancements to the legacy system were still required to run the business. That slowed modernized application adoption and created continuous drift between old and new. Adapts documentation helped architects detect the gaps and produce a high-fidelity plan to migrate functionality — enabling true migration.
Based on an anonymized customer engagement. The customer is not named. Metrics reflect that project’s outcomes; results vary by estate.
2M
lines of code
Legacy+New
dual-system drift
Ongoing
legacy enhancements
True migrate
high-fidelity plan
01 · The Sunset problem
Deprecate the legacy — while the business still needs it.
Sunset programs assume the modernized application will absorb live shipment workloads. In practice, every week of business change lands as another legacy enhancement — and the new stack falls further behind without anyone seeing the full gap.
02 · Dual-system drift
Adoption fails when parity is a guess.
Operators stay on the system that works under load. If the modernized app cannot prove coverage of live legacy behavior, adoption stalls — and the sunset date becomes theater.
Legacy vs modernized
Two stacks. One business. Growing distance.
Legacy (still changing)
- Business-critical shipment flows
- Continuous enhancements for live ops
- Undocumented edge cases and exceptions
- Source of truth for what “works today”
Modernized app (adoption lag)
- Partial feature coverage vs legacy
- Assumed parity without evidence
- Users bounce back to legacy under load
- Sunset date slips as gaps appear late
Adapts documentationDetect gaps · high-fidelity migrate plan · enable true sunset
03 · Challenge
Where sunset programs stall.
| Pressure point | What was hard | What was needed |
|---|---|---|
| Legacy deprecation | The program intended to sunset the legacy shipment platform, but the business still needed continuous enhancements on the old system. | A trusted inventory of what still only exists in legacy — and what can move without breaking ops. |
| Modernized adoption | The new application could not absorb live traffic while parity was incomplete; users stayed on legacy under operational pressure. | Evidence-backed gap detection between old and new so adoption follows capability, not a calendar. |
| Continuous dual-system drift | Every legacy enhancement widened the gap with the modernized stack — migration became a moving target. | Living documentation that tracks both estates so architects can plan true migration, not perpetual coexistence. |
04 · Approach
Document both estates. Plan the real migrate.
Adapts documentation gave architects a shared map of legacy and modernized shipment functionality — so gaps were detectable, ordered, and migratable instead of discovered in production cutover.
| Dimension | Before HC3 | With HC3 |
|---|---|---|
| Gap detection | Parity assumed from feature lists and tribal knowledge across 2M LOC. | Adapts documentation surfaces concrete gaps between legacy and modernized shipment functionality. |
| Migration planning | Sunset dates set without a high-fidelity map of what must move first. | Architects get a high-fidelity plan to migrate functionality in order — enabling true migration. |
| Enhancement vs sunset | Legacy keep-alive work silently undoes modernization progress. | Enhancements and migration waves share one ontology so drift is visible before cutover risk compounds. |
05 · Outcomes
Gaps visible. Migration credible. Sunset possible.
Detection
Old ↔ new gaps
Architects used Adapts documentation to see where the modernized app still lagged the live legacy system.
Outcome
True migration
A high-fidelity plan to migrate functionality — so sunset is earned by coverage, not declared by date.
See it on your codebase
See how HC3 closes the Sunset gap on shipment estates.
30-minute technical walkthrough with an enterprise architect. No slides · a live demo on real code.