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Incremental Core Replacement

Big-bang migrations destroy banks. Fernel enables a strangler-fig architecture. Extract ledgers and payments module by module.

Legacy mainframes run on batch processing. They cannot support 24/7 instant payments or real-time ledger reads. Ripping them out entirely is a multi-year risk.

The alternative, the one that works, is incremental. Run the new system alongside the old one. Migrate one product line, one payment type, one customer segment at a time. Prove value at each step. The old core shrinks gradually. The new one grows.

How FERNEL Fits Your Stack

Your NeedFERNEL CapabilityModule
Incremental adoptionModular architecture. Adopt the ledger first, payments later, compliance when ready.Ledger
Run alongside legacyMulti-tenant isolation. FERNEL operates as a parallel core for new products.Ledger
ISO 20022 nativeNo format conversion layer. Native message models for clearing integration.Connectivity
Standards-based integrationcamt.053 statement import, reconciliation against legacy GLConnectivity
Durable workflowsPayment execution, account migration as orchestrated, recoverable processesWorkflows
DORA alignmentArchitecture designed for DORA Art. 5-27 requirementsSecurity

The Sidecar Pattern

Fernel runs parallel to the legacy core. Synchronize state continuously. Move workloads when you are ready.

Existing Bank InfrastructureCurrent operationsLegacy Core + FERNEL (parallel)Old products + new products side by sideReconciliation Layercamt.053 import, GL mapping

Start Small. Prove Value. Then Scale.

Talk to our team about your core modernization strategy.