Legacy System Decomposition Techniques for Public Sector Cloud Migrations

The transformation towards digital in the public sector equally calls for the modernization of legacy infrastructure. But the inflexibility and monoletheism of the platform makes it difficult for crusher manufacturers to follow suit. This paper provides an in-depth analysis of the legacy system decomposition methods, specially tailored for public sector cloud migrations. We classify and assess structural, behavioral, and data-driven decomposition, which soundness, scalability, and risk conditions should be satisfied in the public governance domain. Based on a hybrid approach combining service-oriented decomposition, domain-driven design, and automated refactoring, we provide a strategic approach for gradually decoupling legacy components while ensuring data integrity and regulatory compliance. A case study of a government accounting system migration to a cloud-native platform is conducted to demonstrate the power of proposed framework. The findings show a stronger modularization, a gain in technical debt and in agility of the migration process. We believe that our results provide practical implications and methodological recommendations for architects and policy makers working in the context of public sector digital modernization