898975372-Leaving-Legacy-Software-Behind-a-Modern-Migration-Roadmap.pdf

Legacy software can hold your business back—slowing operations, inflating costs, and limiting innovation. This modern migration roadmap provides a clear, step-by-step guide to assess your current systems, plan and execute a seamless upgrade, strengthen security, and unify integrations. With the right strategy, team, and tools, you can leave outdated technology behind and embrace a future of efficiency, agility, and growth.

1. Leaving Legacy Software
Behind: A Modern Migration
Roadmap
Legacy systems continue to be a significant challenge for organisations across
India and globally. As we navigate the digital landscape of 2025, modernisation has
become more than just a technical upgrade—it's a strategic imperative for
enterprises looking to remain competitive, secure, and efficient.
This roadmap provides a comprehensive guide to successfully migrating from
legacy systems to modern architectures, highlighting key considerations,
strategies, and best practices developed from successful transformations in the
Indian market and beyond.

2. The State of Legacy Systems Today
Despite rapid technological advancement, legacy software remains
deeply embedded in enterprise infrastructure. According to recent
Gartner research (2024), a staggering 73% of global enterprises still run
critical operations on legacy systems, with similar patterns observed
across Indian industries.
These outdated systems create significant financial burden, with
organisations spending up to 70% of their IT budgets simply
maintaining legacy infrastructure—resources that could be directed
toward innovation and growth initiatives.
Security Vulnerabilities
Outdated systems often lack modern security features and
patches, creating significant exposure to cyber threats.
Compliance Challenges
Legacy systems struggle to meet evolving regulatory
requirements like India's DPDP Act and global standards.
Innovation Barriers
Rigid architectures prevent integration with modern technologies
like AI, blockchain, and cloud services.
The technical debt accumulated in these systems creates a compounding problem that becomes more expensive and risky to address with each
passing year.

3. Why Migrate? Business Drivers & Opportunities
Opportunity Cost
Legacy systems significantly slow
digital transformation initiatives. For
every month delayed in
modernisation, organisations lose an
estimated ₹50-75 lakhs in potential
revenue opportunities and
operational efficiencies.
Regulatory Pressure
Compliance with GDPR, India's Digital
Personal Data Protection Act, and
sector-specific regulations is
increasingly difficult with legacy
systems, exposing organisations to
potential penalties.
Cost Reduction
Post-migration, organisations
typically reduce operational costs by
30-50%. This includes lower
maintenance costs, reduced
downtime, and decreased need for
specialised legacy expertise.
Success Story: State Bank of India
SBI's strategic mainframe migration to cloud infrastructure improved system uptime from 95% to 99.9%, reduced transaction
processing time by 65%, and enabled the launch of 12 new digital banking services within the first year post-migration.

4. Laying the Groundwork: Assessment
& Discovery
1Architecture Mapping
Document current system architecture, identifying components, dependencies, interfaces,
and critical data flows. Create detailed diagrams of how systems interconnect.
2Stakeholder Engagement
Conduct thorough interviews with business users, IT teams, and leadership to understand
pain points, undocumented workflows, and business-critical functions.
3Gap Analysis
Identify compliance gaps, technical debt zones, and security vulnerabilities that need
addressing during migration.
4Success Metrics
Define clear, measurable KPIs for migration success, including system performance
(uptime, response time), business outcomes, and ROI targets.
This discovery phase typically requires 4-6 weeks for mid-sized systems but may extend to 3-4
months for complex enterprise applications with numerous integrations and dependencies.

5. Planning & Designing the Modernisation Roadmap
Strategy Selection
Based on the assessment, determine which approach aligns with your business goals, technical requirements, and risk
appetite:
•Rehost: Move as-is to modern infrastructure
•Refactor: Modernize code while preserving core functionality
•Replatform: Change underlying platform with minimal code changes
•Replace: Build new system and retire legacy application
Target Architecture
Design your future-state architecture considering:
•Cloud platform selection (AWS, Azure, GCP, or hybrid)
•Microservices vs. monolithic approach
•Data migration and transformation strategy
•Integration patterns and API strategy
•Security and compliance requirements
Testing & Deployment
Implementation
Planning
Discovery
Document dependencies thoroughly and establish project milestones using agile sprints (typically 2-week cycles) to maintain momentum while allowing for course correction as needed.

6. Choosing the Right Migration Strategy
Strategy Description Best For Indian Example
Rehost "Lift-and-shift" to modern infrastructure with minimal changesQuick wins, low risk toleranceHDFC Bank's on-premises systems to Azure migration
Refactor Redesign core modules while preserving business logicComplex, custom applicationsTCS's COBOL to Java transformation for insurance client
Replatform Change underlying platform with minimal code modificationApplications with solid core logicReliance Jio's mainframe to AWS Lambda migration
Replace Build new system from scratch, retire legacy applicationFundamentally outdated systemsAirtel's legacy ERP replacement with SAP S/4HANA
Low Technical Complexity
Low Business Value
High Technical Complexity
High Business Value
Replace - High Complexity, Low ValueReplatform - Low Complexity, Low Value
Refactor - High Complexity, High ValueRehost - Low Complexity, High Value
Selection criteria should include cost considerations, timeline requirements, available expertise, and organisational risk tolerance. Most successful enterprises employ a combination of strategies across different system components.

7. Implementation: From Pilot to Full Rollout
Pilot Migration
Begin with a controlled pilot to validate your approach, test
processes, and demonstrate ROI. Select a non-critical but
representative component to minimise business risk while
maximizing learning.
Incremental Deployment
Implement changes in small, manageable increments using
cloud-native technologies for new components. Popular choices
in the Indian market include Django, Node.js, React, and
AWS/Azure managed services.
Parallel Operations
Run old and new systems simultaneously during transition to
verify data integrity and system behaviour. This approach
minimises disruption but requires careful synchronisation.
Continuous Feedback
Implement regular standups, retrospectives, and roadmap checks
to prevent drift and address issues promptly. This agile approach
has proven particularly effective for Indian enterprises managing
complex migrations.
According to Infosys research, organisations that implement this phased approach with continuous feedback loops experience 40% fewer
post-migration issues than those pursuing "big bang" cutover strategies.

8. Common Pitfalls & Risk Management
Data Integrity Risks
Legacy data often contains inconsistencies, duplicate records,
and formatting issues that can cause migration failures.
Implement robust data cleaning, validation rules, and
comprehensive backup strategies before migration begins.
Hidden Dependencies
Undocumented interfaces and dependencies frequently break
during migration. Use dependency mapping tools and conduct
thorough testing to identify these connections before they cause
production issues.
Cost Management
Cloud migrations often exceed budgets due to overlooked
elements like data transfer costs, storage requirements, and
specialized consulting. Implement cloud cost monitoring tools
and regular financial reviews.
Security & Compliance
New environments may not meet the same security and
compliance standards as legacy systems. Conduct thorough
security assessments and compliance checks at each migration
stage.
Risk Mitigation Tip: Create a dedicated "SWAT team" of legacy system experts and modern architecture specialists who can quickly
troubleshoot issues during the migration process. This approach reduced critical incidents by 65% during Infosys's banking client
migrations.

9. Post-Migration: Validation and Optimization
Validation Testing
Implement rigorous automated and user acceptance testing to ensure all functions
work correctly. Include edge cases and stress testing to validate system resilience.
Performance Monitoring
Deploy comprehensive monitoring tools to track system performance, user
experience, and business metrics. Establish feedback loops for continuous
improvement.
Legacy Decommissioning
Only after thorough validation, begin the process of decommissioning legacy
systems to eliminate redundant costs and maintenance overhead.
Success Metrics to Track
50%
Incident Reduction
Target 50% reduction in incident reports within 6 months post-migration
30%
Cost Savings
Minimum 30% reduction in operational costs compared to legacy maintenance
99.9%
System Availability
Target uptime of 99.9% or better for mission-critical systems
40%
Development Speed
40% reduction in time-to-market for new features and enhancements
The optimization phase is critical for realizing the full value of your migration investment. Plan for a dedicated 3-6 month period of fine-tuning and optimization to achieve target performance metrics.

10. Conclusion: Modernisation as a Continuous Journey
Legacy system migration is not a one-time project but an ongoing journey of continuous improvement. The most successful organisations approach modernisation as
an evolutionary process rather than a discrete event.
Regular Assessment
Continuously evaluate your technology stack
against business needs and market innovations.
Future-Ready Architecture
Design systems with modularity, scalability, and
flexibility to prevent future legacy debt.
Skills Evolution
Invest in upskilling teams to maintain and enhance
modern systems.
Innovation Integration
Establish processes to evaluate and incorporate
emerging technologies.
By embracing this continuous approach to modernisation, organisations can achieve sustainable digital transformation that delivers lasting business value: reduced
costs, enhanced innovation capabilities, improved customer experiences, and greater business agility in responding to market changes.
The journey away from legacy systems is challenging but essential for any organisation looking to thrive in today's digital economy.