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Case Study

Landesbank Hessen-Thüringen – Helaba

Transformation in the Enterprise environment:
The core banking system of Helaba

With eXplain from PKS, we were able to remove a considerable amount of code that was no longer required in our Natural and Cobol-based core banking system. eXplain enabled us to fundamentally clean up and purge the system. The documentation created fully automatically by eXplain also comprehensively meets our audit requirements. These are just two examples of how eXplain supports us in our project „stabilization of the core banking system”. I would also like to emphasize the extremely pleasant cooperation with the competent team at PKS as well as the flexible possibilities in everyday project work. Helaba-specific requirements could be taken into consideration at any time.

The initial situation

The core banking system at Helaba, one of the key parts of the company, has been running on an IBM mainframe environment since 1979 and is essentially based on Adabas, Natural and Cobol technologies. The system was continuously developed and expanded over a period of 20 years until it was more or less frozen shortly after the turn of the millennium and remained in use at this level until 2016.

As a stable backbone of Helaba it has always performed well and is currently supported by a team of 10 internal and 5 external developers. However, due to strategic considerations, the replacement of the core banking system with SAP standard software was tackled in 2016. The prevailing complexity in the system, with over 3,000 interfaces and incomplete technical and specialist documentation, was the reason why the cost of the changeover had to be put in the three-digit million range.

After only a short time, the implementation project had to be postponed to 2017 due to higher-priority regulatory project plans. At the same time, there were regulatory requirements which resulted in an acute need for action in the inventory system.

Complication and challenges

At the end of the considerations, it was clear to all those involved at Helaba that no matter where the journey with the core banking system might take us - no matter what new system is to come - there will be years of coexistence between the old and new systems. This also means that there will be a shortage of personnel and know-how that must be counteracted.

One of the most important findings was also that the step-by-step changeover to a new system, which is considered realistic, will only be possible if the existing system is simplified in terms of complexity and the over 3,000 interfaces are massively reduced or structured.

The pain points were obvious:

How to get an overview of the legacy system?

How to build up new resources to manage ongoing operations and the transition phase of 5-7 years?

How can complexity be reduced and a component-based migration to the new system be made?

The Helaba project team found central support for the solution of the problem in eXplain and in cooperation with PKS.

eXplain helps to create transparency, to penetrate the core banking system technically and professionally and thus to open up essential possibilities for the future

Establish a roadmap for stabilising the core banking system

Perform supporting analyses of data flow and object usage

Identify interfaces between the applications

To document the application interfaces with DV documentation in an audit-proof way

Simply transfer knowledge to new employees

Prepare a changeover in the best possible way, so that it can be carried out at low risk and at optimal cost

Step 1

Implementation of demo sessions and workshops to introduce the functionalities and possibilities that eXplain can offer Helaba - combined with the provision of experienced software architects in the context of legacy transformation

Step 2

Request for proposal by Helaba for a proof of concept for the analysis and documentation of the core banking system

Step 3

PKS can convince in the bidding process and performs a PoC with eXplain

Step 4

After successfully completing the PoC, eXplain is rolled out to the entire system

Step 5

The complexity is reduced and the system is prepared optimally for the target system which is still to be defined


The intensive analysis of the core banking system has raised the question of whether a modernisation and restructuring of the core banking system can also be a valid option for complete replacement. The idea would be to encapsulate functionality, make it available via web services and therefore make the overall architecture more modular, technologically, flexible and efficient.

Helaba‘s requirements for eXplain were demanding and the core banking application and its interfaces very complex. Once again, we have shown that our innovative analysis technology can also optimally cover customer-specific features. The feedback on the utility value of eXplain was already clear during the introductory event, so a rollout is now planned for the entire team.

The advantages for the customer

The massive cost pressure can be reduced by safely removing ballast in the grown core banking system and by using modern technologies that save developers and architects time and money in their daily work
Security, transparency and control over the running system are regained
Filling the staff gap in the development team: either internal or external resources
Thanks to improved architecture in the legacy system, it is possible to use modern technologies on the host and be prepared for all paths into the future

Tools / Procedure

  • Proof of Concept
  • eXplain
  • Clustering
  • Complexity Survey
  • Cleanup and Bereinigung
  • Training and Coaching

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