The challenges of monolithic ERP systems in the public sector
Legacy ERP systems in public institutions hinder adaptation to modern requirements. Any update or integration with new government services takes 3 to 6 months and often requires system downtime. This prompts departments to create their own informal IT workarounds, slowing down the launch of e-services and adaptation to legislative changes.
The monolithic architecture of ERP systems built decades ago did not account for flexible integration with external services or mobile applications. A change in one module poses risks to the entire system. Instead of trying to revive the monolith or replace it all at once, it is more practical to apply phased decomposition—decoupling individual functions into microservices with API access.
The "big bang" mistake and the benefits of phased migration
The most common mistake when modernizing legacy systems is attempting to replace the entire infrastructure (ERP, ECM, or DMS) in a single massive project. Due to thousands of hidden dependencies, such initiatives often exceed budgets, drag on for years, or lead to business process disruption.
The alternative is a phased migration, which involves:
- selecting a single functional area or process;
- moving it to a new system;
- running the old and new systems in parallel;
- gradually transitioning users.
This approach helps mitigate risks and deliver quick wins.
Practical decomposition and approach risks
For public authorities handling large volumes of citizen inquiries, offloading specific modules to modern low-code BPM platforms is highly effective. This enables the creation of flexible workflows, integration with state registries (such as the Diia portal) via APIs, and mobile access in parallel with the legacy system's operation.
However, decomposition has its limitations. It is not suitable if the legacy ERP architecture is too tangled to isolate individual blocks, or if the organization is not ready to run two systems in parallel. Before starting modernization, it is essential to audit key business processes and identify a few highly critical functions to migrate first.
Why it matters for the industry
For the public sector and IT vendors, relying on rigid legacy ERPs delays digital transformation and increases maintenance costs. Failing to modernize means slower public service delivery, security vulnerabilities, and an inability to integrate with modern national platforms like Diia, ultimately widening the gap between government services and citizen expectations.
Steps for businesses
- Conduct a comprehensive audit of key business processes to identify dependencies and isolate individual blocks.
- Avoid "big bang" replacements; instead, opt for a phased migration by isolating and moving one functional area at a time.
- Decompose monolithic functions into microservices with API access.
- Offload specific modules to modern low-code BPM platforms to enable flexible workflows and integration with state registries.
- Run old and new systems in parallel to mitigate operational risks during transition.
Prepared by a Software Ukraine member. Original publication.