Software Maintenance Challenges in Legacy Systems at Federal Government Ministries in Abuja

Legacy software systems in Nigerian federal government ministries represent a significant technical and financial liability, with many critical applications running on outdated platforms that are costly to maintain and incompatible with modern integration requirements. This study examines software maintenance challenges in legacy systems operated by federal government ministries in Abuja's North Central zone, covering the Ministries of Finance, Education, and Health. Using a descriptive qualitative design, data is collected through structured interviews with 22 government software engineers and IT managers. Analysis employs Lehman's laws of software evolution as a theoretical lens, mapping maintenance challenges against entropy growth, adaptive maintenance demand, and conservation of familiarity. Findings identify outdated COBOL and FoxPro codebases, absent documentation, staff knowledge attrition, and vendor lock-in as the dominant maintenance challenges. Budget constraints prevent full system replacement, creating a costly patch-and-maintain cycle. The study proposes a legacy modernisation roadmap combining incremental refactoring, API wrapping for integration, and knowledge transfer protocols to address documentation gaps. Professional recommendations emphasise modular modernisation over big-bang replacement and the establishment of a government-wide software asset inventory. This research provides a practitioner-level assessment of legacy maintenance realities in Nigeria's public sector ICT landscape. Keywords: legacy systems, software maintenance, federal government, Abuja, modernisation