UK Legacy Software Modernisation Guide (2026)

ClickMasters legacy modernisation timelines: (1) Single module Strangler Fig (replace one module of a legacy system — e.g., customer portal only): 8–16 weeks. (2) Full application modernisation (PHP 5/7 → Node.js/React, same feature set): 24–48 weeks. (3) NHS HealthTech FHIR R3→R4 migration (all NHS integrations): 14–22 weeks. (4) FCA Consumer Duty legacy UX remediation (journey fixes, readability, cancellation): 8–14 weeks. (5) HMRC CDS migration from CHIEF: 8–16 weeks. Strangler Fig allows partial value delivery — the first module is live in 8–16 weeks even if the full modernisation takes 2 years. ClickMasters always delivers the highest regulatory pressure module first.

The biggest UK legacy modernisation risk is data loss during migration — particularly for NHS health records (Article 9 special category) and FCA financial records (5-year retention). ClickMasters data migration approach: (1) never delete from source until destination is verified (source and destination compared record-by-record before source decommission), (2) migration validation (every migrated record has a checksum — destination checksum must match source), (3) 30-day parallel period (both systems contain the data for 30 days after migration — any discrepancy discovered and reconciled before source deleted), (4) point-in-time restore (destination database snapshot before migration — can restore to pre-migration state within 5 minutes if catastrophic data issue discovered). Data migration risk is engineering risk, not business risk — ClickMasters engineering controls eliminate it.