Abstract
Legacy systems are existing systems that still sustain critical business processes. Due to their robustness and value, such systems often form organisations' backbones. However, these systems are inflexible and have many maintainability and scalability issues. Thus, they need to be modernised and migrated to new paradigms that offer agility, cost reduction, and operational efficiency. To accomplish this goal, this paper provides a review of case studies drawn from various domains and using diverse migration techniques. However, not all the migration approaches provide details of how to migrate successfully. The quality metrics and requirements of the migration process still need to be considered. Therefore, a system migration life cycle (SMLC) is presented as a generic and adaptable framework that can be used (fully or partially) for a large number of legacy applications. This paper also focuses on the pre-migration stage of SMLC and it shows how to use AHP to design a unique pathway based on business motivations and user requirements.