Legacy Modernization for Financial Services & Banks: The Way to the Digital Future

Legacy Modernization for Financial Services & Banks: The Way to the Digital Future

The most important thing in the short term: In many banks, up to 80% of the IT budget flows into the maintenance of legacy systems ([Source.

Red Hat](Redhat (redhat.com, external source) services/how-to-accelerate-modernizing-legacy-banking)). Modernization via microservices, cloud infrastructure and the Strangler Pattern allows step-by-step detachment without operating interruption – with the result.

Faster time-to-market, open-banking capability and real-time fraud detection.

The financial sector is facing a profound change.

Driven by new digital competitors (FinTechs), changing customer goals and a steadily more complex regulatory system, banks and financial service providers need to refocus their business models and, above all, their technical base.

At the heart of this digital transformation is the urgent need to modernize the often decades-old Legacy systems.

These old systems, which in many cases are still based on mainframes and programming languages such as COBOL, are stable, but they have become innovation brake.

This complete blog post highlights why the Legacy moderation for banks is not only an option but a survival need.

We analyse the key challenges, the enormous benefits of a modern IT architecture, and present concrete applications as well as proven strategies for successful IT-modernisation in finance.

Why Legacy Systems Be Loaded in the Financial Industry

The financial sector is facing a profound change.

For Legacy Modernization for Financial Services & Banks. The Way to the…, Legacy Modernisation, Cost Calculator. Legacy Modernisation, [Solution.

Legacy Reduction](/en/solutions/legacy-reduction) sowie Monolith vs. Microservices help you align rollout, scope and budget before you commit.

The stability and reliability of legacy systems that have carried the most critical business processes of banks over decades is indisputable.

But this stability comes at a high price.

The disadvantages of outdated IT infrastructures manifest in three critical areas: cost, agility and security.

High operating costs and inefficiency

The maintenance and operation of legacy systems are a major part of the IT budget.

Experts estimate that up to 80% of IT expenditure is spent in many financial institutions alone (Source: Red Hat).

• **The knowledge about the often proprietary and outdated technologies (e.g. COBOL, PL/I) is sown. The few remaining experts are expensive, and young people lack.

• Complex maintenance: Every small change or extension in monolithic architecture is extremely expensive, susceptible to errors and requires long test cycles. .* Inefficient scaling: The scaling of mainframe capacities is disproportionately expensive and inflexible compared to modern cloud solutions.

Lack of agility and innovation brake

Legacy systems cannot compete in a world where customers expect real-time services and tailored offers. They are the main reason for a slow time-to-market of new products.

• Monolithic structure: The rigid monolithic architecture prevents the rapid rollout of new functions.

  New digital services such as mobile apps or new credit platforms often need to be connected to the old systems via complicated and error-prone interfaces.

• Delayed reaction to competition: FinTechs can market new products in weeks thanks to their modern, cloud-native architectures, while proven banks need months or years.

• Data-Silos: Data are often trapped in different, isolated legacy systems, which makes a holistic customer vision and the use of big data or artificial intelligence (AI).

Increased security risks and compliance barriers

Short: Contrary to the rural opinion, legacy systems are not per se safer.

Contrary to the rural opinion, legacy systems are not per se safer. They represent a growing risk, in specific with regard to compliance with strict regulatory needs.

• Old security protocols: The security protocols and encryption mechanisms of many old systems are not designed for today's threat landscapes.

  Patches and updates for critical vulnerabilities are often no longer available.

• Regulatory needs: Rules such as PSD2 (Payment Services Directive 2), DORA (Digital Operational Resilience Act) or BaFin needs require high clarity, access and quick adjustment.

  The complexity of the legacy systems makes compliance with these needs an administrative and technical nightmare.

The central advantages of legacymodernization

Legacy Moderation is the key to overcome these challenges and to ensure market strength in the long term.

The benefits of a transition to a modern, cloud-capable architecture are manifold and have a direct impact on the business outcome.

Accelerated time-to-market and higher innovative power

By switching to modern architectures, in specific microservices and API gateways, financial institutions regain the needed agility. .* Microservices architecture: Monoliths are dismantled into small, separate services.

Each team can develop, test and deploy its service independently.

This enables a continuous provision (CI/CD) and shortens the development cycles from months to weeks or even days.

• Open Banking and APIs: The provision of standard APIs (Application Programming Interfaces) is the basis for Open Banking. Banks can thus seamlessly cooperate with FinTechs and third-party providers, create new ecosystems and offer new products such as aggregated account information or fast credit decisions.

Significant cost reduction and efficiency increase

The shift of workloads from expensive mainframes to flexible, cloud-native platforms leads to massive cost savings.

• Cloud infrastructure: The use of public, private or hybrid clouds (e.g. AWS, Azure, Google Cloud) replaces high investment costs (CAPEX) with flexible operating costs (OPEX).

  The demand-oriented scaling (Pay-as-you-go) improves resource use.

• Automatization: Modern platforms allow complete automation of operation, monitoring and security (DevOps, DevSecOps), which drastically reduces manual effort and error rate.

Improved customer experience and competitiveness

Modernisation enables the provision of services that meet today's customer goals.

• Real-time services: Transactions, payments and credit decisions can be handled in real time, increasing customer satisfaction.

• Omnichannel capability: A modern IT base allows consistent and seamless customer experience across all channels – from branch to mobile app to online portal.

• Personalisation: By consolidating data from different sources, banks can offer highly tailored financial products and consultancy services using KI/ML.

Increased security and regulatory compliance

Modern architectures are safer from scratch and help compliance with regulator technology.

• Zero-Trust architecture: New systems can be built according to the Zero-Trust principle where no user or system is trusted by default.

  This minimizes the risk of internal and external threats.

• Auditability and clarity: Cloud-native platforms provide complete logging and monitoring functions that significantly simplify the auditability and compliance needs (e.g. DORA).

Strategic applications of modernization in banks

Legacy Moderation is not a single project, but a strategic transformation that focuses on specific applications to generate maximum business value.

Modernisation of the core banking system

The **Core Banking System is often the most complex but also the most important project. It concerns central functions such as account management, payment transactions and credit management.

• Step resolution: A Big Bang approach is too risky here. Proven methods such as the Strangler Pattern (Strangler Fig Pattern) allow the step-by-step detachment of functions.

  New services are built parallel to the old system and gradually take over the tasks until the legacy system can be "throttled". And switched off.

• Modular components: The aim is a modular Core Banking system consisting of separate, interchangeable components. This reduces the dependencies and allows future upgrades without operational interruption.

API opening for FinTech collaborations (Open Banking)

Short: Compliance with PSD2 has accelerated the need for API opening.

Compliance with PSD2 has accelerated the need for API opening. However, a modern API strategy goes far beyond that.

• API management: A solid API management system is required to safely control third-party access, monitor performance and ensure compliance with user policies.

• New sources of revenue: By providing high-quality, easy to integrate APIs, banks can unlock new sources of revenue by offering their infrastructure and data as a service (banking as a service).

Data and analysis platforms

The ability to process and analyze large amounts of heterogeneous data is a decisive competitive factor.

• Data Lakes and Data Mesh: Modern cloud platforms enable central data sheets or decentralized data mesh architectures that merge data from legacy and new systems.

• KI/ML applications: On this data base, KI and machine learning applications can be introduced, e.g. for precise credit risk assessment, for optimising marketing campaigns or for predicting customer migration.

Risk management and fraud detection

The modernisation of IT infrastructure enables a major improvement in risk control.

• **Real-time fraud detection:*Old batch processing systems can often detect fraud cases only hours later. Modern, event-driven architectures allow real-time fraud detection and prevention, which minimizes losses and increases safety. . Regulation reporting: The automation of regulatory reporting (e.g. reporting) by modern data pipelines reduces manual effort and error rate.

Successful modernization strategies: The quality of choice

The choice of the right modernization strategy depends on the complexity of the system, the available resources and the desired speed.

The current "6 R's" of modernization provide a framework for decision-making.

• ** ** Rehosting** (Lift & Shift) | Move the application to a cloud infrastructure without code changes. | Fast migration, low complexity. | Gering, but no use of cloud-native benefits. |.
• ** ** Replatforming** | Move the application to the cloud with minimal adjustments to use cloud functions (e.g. Managed Database Services). | Fast added value, low to medium cost. | Means as code adjustments are needed. | | Refactoring (Rearchitecting) | Restructure and rewrite the code to use a cloud-native architecture (microservices). | Maximum added value, full agility. | High as high complexity and time. |.
• ** ** Rebuilding** | Full new development of the application, often while maintaining the core features. | If the old system is no longer to be saved. | Very high, because high effort and risk. |.
• ** ** Retire** | Exemption of systems that are no longer needed. | Immediate cost reduction. Gering. |.
• ** ** Retain** | Retaining the system as it fulfils its purpose and modernisation does not bring added value. | Rare in the core banking sector. | Medium to high (hidden costs). |.

The Strangler-Pattern approach: risk mitigation by step-by-step detachment

For the critical Core banking systems, the Strangler Pattern has proven itself as the safest and most effective method.

Instead of replacing the entire system at once (Big Bang), a facade (Proxy) is switched in front of the legacy system.

New features are built as modern microservices and integrated into this façade.

1. Identification: The most critical or most frequently modified functions are identified (e.g. account balance query).

Development: The new function is built as a microservice in a modern environment (e.g. Kubernetes).

3. **The proxy converts the traffic for this specific function to the new microservice. All other inquiries continue to go to the legacy system. .4. Repeat: This process is repeated function for function until the legacy system has been completely "restricted" by the new services and can be switched off.

This approach minimizes the risk of interruptions in operation since the old system serves as a fallback solution as long as the new services are not yet fully stable.

Conclusion: Now act for digital resilience

The Legacy Modernization for Financial Services & Banks is a marathon, not a sprint.

It requires a clear strategy, technical expertise and a deep understanding of the regulatory needs of the industry.

The cost of non-trade – in the form of lost revenue, increased security risks and the loss of market shares to agile competitors – exceeds investment costs by far.

The future of banking is digital, agile and cloud-native.

Only those who modernize their technical base can meet the needs of Open Banking, real-time services and AI-based personalization and secure the digital resilience of their company.

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**Call to Action

**You are facing the challenge of modernising your Core Banking system or developing a secure cloud strategy? * *

The Legacy transformation is complex but can be successfully introduced with the right partner on your side.

Groenewold IT Solutions is your competent partner for IT moderation in finance.

We have expertise in modern cloud architectures, microservices and proven migration strategies such as the Strangler Pattern to gradually and risk-minimumize your critical systems into the digital future.

**Contact us today for a non-binding initial advice and lay the foundation for the agility and security of your IT infrastructure. **

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References

[1] Red Hat. * Accelerated modernisation of legacy banking systems*. URL: Redhat (redhat.com, external source)

[2] adesso. Legacy modernization for banks. URL: Adesso (adesso.de, external source)

[3] OpenLegacy. Legacy Banking Systems: Why and how to Modernize. URL: Openlegacy (openlegacy.com, external source)

[4] Groenewold IT Solutions. To modernize legacy systems: a guide. URL: https://www.groenewold-it.solutions/blog/legacy/legacy-systems-modernisation-one-leit Thread

[5] Baringa. Legacy Tech Infrastructure Remains a Challenge for Banks. URL: Baringa (baringa.com, external source)

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Further articles

Interfaces & APIs for other industries

• Interfaces & APIs for Education & Research.
• Interfaces & APIs for financial services.
• interfaces & APIs for healthcare.
• Interfaces & APIs for Retail.
• interfaces & APIs for crafts & services.
• interfaces & APIs for real estate & construction.
• Interfaces & APIs for Logistics & Transport.
• Interfaces & APIs for Production & Manufacturing.
• Interfaces & APIs for Public Administration.

More IT solutions for energy & supply

• App development for energy & supply.
• KI solutions for energy & supply.
• Legacy Modernization for Energy & Supply.
• Odoo ERP & CRM for Energy & Supply.
• Software Recovery for Energy & Supply.
• Maintenance & Support for Energy & Supply.

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You are interested in interfaces & APIs? Learn more on our performance page interfaces & APIs or contact us for non-binding advice.

Frequently Asked Questions (FAQ)

What is this article about: “Legacy Modernization for Financial Services & Banks: The Way to the Digital Future”?

Here we cover Legacy Modernization for Financial Services & Banks. The Way to the Digital Future — focused on architecture, process, and business outcomes.

The financial sector is facing a profound change.

Driven by new digital competitors (FinTechs), changing customer goals and a steadily more complex regulatory system, banks and financial service providers need their business mode...

Who benefits most from the content described here?

Typical readers are business and IT leaders in Legacy-Modernisierung who want to secure quality, security, and ease of upkeep over the long term.

How does this topic fit into an IT or digital strategy?

In a digital strategy, prioritize stable core processes first, then extensions. See also professional software development and consulting.

For multi-system landscapes, IT consulting and architecture helps align vendors and internal teams.

What are sensible next steps if we need support?

If you need support with design, delivery, or modernization: schedule an appointment or outline your project via contact.

References and further reading

The following separate references complement the topics in this article:

• Bitkom – German digital industry association.
• German Federal Office for Information Security (BSI).
• European Commission – Digital strategy.
• MDN Web Docs (Mozilla)
• W3C – World Wide Web Consortium.