Legacy information systems continue to underpin critical operations across industries such as banking, government, manufacturing, and large-scale enterprises. While these systems provide stability and institutional memory, they also introduce significant challenges related to scalability, security, interoperability, maintainability, and innovation velocity. Recent advances in artificial intelligence, including machine learning, predictive analytics, and generative AI, have emerged as transformative forces capable of re-engineering legacy systems rather than merely replacing them. This research article presents an in-depth, theory-driven and practice-oriented examination of AI-enabled legacy system modernization, with particular emphasis on augmented intelligence, quality assurance transformation, and human–AI collaboration. Drawing strictly on the provided academic, industry, and thought-leadership references, the study synthesizes multidisciplinary perspectives from software engineering, digital transformation, cybersecurity, organizational strategy, and human–computer interaction. The article develops a conceptual framework explaining how AI techniques support incremental migration, automated code abstraction, predictive quality assurance, and continuous system evolution, while simultaneously addressing governance, data privacy, cybersecurity, and ethical considerations. A qualitative methodological approach is adopted, integrating comparative analysis of existing frameworks, thematic synthesis of case-based insights, and interpretive evaluation of reported outcomes. The findings reveal that AI-driven modernization is not a purely technical endeavor but a socio-technical transformation requiring augmented intelligence models that balance automation with human judgment. The discussion critically evaluates limitations, including algorithmic bias, skills gaps, and integration complexity, and outlines future research directions related to resilient architectures, explainable AI, and adaptive governance. The article concludes that AI-enabled legacy modernization represents a foundational pathway for sustainable digital transformation when aligned with human-centric design and strategic oversight.

Error budgets, which come from Service Level Objectives (SLOs), are a way to measure and control the trade-off between the speed of software supply and the risk of reliability. Error budgets are common in modern SRE practice, but they are harder to use in banks because of operational resilience standards, tight auditability, third-party concentration risk, and the fact that disruptions affect customers and markets in different ways. This paper presents the Finance Error Budgeting Framework (FEBF): a governance-conscious, dependency-based, and regulation-aligned error budgeting approach intended for financial SRE teams. FEBF brings in (i) risk-tiered SLO design that is in line with important business services, (ii) dual-ledger burn attribution across service and dependency layers, (iii) burn-rate-driven release governance and change control integration, and (iv) evidence-ready artifacts that meet the operational resilience standards of DORA, FFIEC, and PRA. We offer clear definitions, a plan for how to put them into action, flowcharts, tables and chart specifications for empirical evaluation, and a policy playbook that is ready for use in a business. The result is a model that works, can be scaled up, and makes incidents more likely to end well while making it easier to defend against regulatory action.

The accelerating digitization of organizational infrastructures, combined with the erosion of traditional network boundaries, has rendered perimeter-based security models increasingly ineffective. In response, Zero Trust Architecture (ZTA) has emerged as a dominant paradigm advocating continuous verification, least-privilege access, and strict identity-centric enforcement mechanisms. However, despite its conceptual clarity and growing institutional adoption, Zero Trust remains unevenly implemented, often narrowly interpreted as a technological solution rather than a comprehensive socio-technical security transformation. This article presents an extensive, theory-driven examination of Zero Trust Architecture by synthesizing foundational Zero Trust literature with research on secure messaging protocols, software-defined perimeters, and human-centered security challenges such as security fatigue and authentication usability. Drawing strictly from the provided corpus of standards documents, industrial frameworks, and empirical studies, this research reconceptualizes Zero Trust as an integrated ecosystem that unifies protocol-level trust negotiation, identity-aware network access, and user experience considerations. The methodology adopts a qualitative analytical approach grounded in comparative framework analysis, conceptual mapping, and interpretive synthesis of existing standards and peer-reviewed findings. The results demonstrate that successful Zero Trust implementation depends not only on architectural enforcement but also on adaptive authentication workflows, secure information exchange mechanisms such as XMPP-based security signaling, and organizational sensitivity to human cognitive load. The discussion critically interrogates prevailing assumptions within Zero Trust discourse, highlights structural and behavioral limitations, and proposes directions for future research emphasizing interoperability, automation, and resilience against security fatigue. By positioning Zero Trust as a dynamic governance model rather than a static control framework, this article contributes a holistic perspective essential for both academic inquiry and large-scale operational deployment