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Legacy Modernization: Are you ready?

Author: Jitendra Jain, Senior Technology Architect (HILife - Architecture & Design Group)


Legacy modernization: Let us understand what is it ?

Legacy modernization can be conceptualized as a continuous transformation journey for organizations to radically improve their product services, business processes, applications, platform, environment and infrastructure. Legacy modernization typically involves consolidation of legacy software and hardware in alignment with the latest business needs based on cutting edge technologies. In modern competitive fast growing industry timely revision of older systems has become a basic necessity for survival. Organizations are in do or die situation has no option left other than modernizing their legacy systems as soon as possible to be in the game as it has directly or indirectly impacting their business growth.

Organizations from banking, finance, insurance, healthcare, retail, life sciences and telecom sector is aggressively becoming part of this modernization journey to retain their customers and businesses. Scalability, flexibility, accuracy and high performance along with Omni channel experience is becoming de-facto standard in this rapidly changing world.

Top tech buzz words like mobility, cloud, big data, analytics, artificial intelligence, automation, Chatbots, digitization etc. is some of the key technology drivers which can be considered and applied during modernization process. 

Biggest Question for Organizations " What should I do exactly ?"


Major issues with Legacy Systems : "I can't maintain legacy systems anymore, It even does't meet business needs. Are they useless?"

Some of the major challenges are highlighted below. They eventually becomes key factors for driving the whole transformation journey. 

  • Application design limitations
  • Damn slow non-scalable, non-distributed systems
  • Lack of IT Staff to maintain legacy systems
  • High maintenance and enhancements cost factor
  • Longer time to market
  • Obsolete & Outdated software & hardware (Technology + Infrastructure)
  • Monolithic architecture issues
  • Integration challenges due to tightly coupled application
  • Fail to meet business objective
  • Regulatory compliance factors 

Legacy modernization transformation challenges: "It is not a vanilla ice cream folks, path will be full of hurdles , keep it in mind"

It is not very easy to transform existing legacy systems. Successful implementation requires huge effort, CIO's vision and solid strategic plan. The real optimal execution path typically comes with various hurdles and roadblocks. Some of the key roadblocks listed below.

  • Lack of strategy & vision
  • Lack of skilled professionals
  • Longer development cycles
  • Legacy Technology (e.g. AS400, RPG, COBOL, PowerBuilder, Batch Jobs, Informix, FoxPro, VB, C etc.)
  • Existing re-usability of legacy systems
  • Business process changes
  • Huge modernization effort
  • Lack of agility
  • Changes to underlying architecture
  • Overall cost of modernization
  • Data migration and data synchronization issues
  • Dependency on legacy platform
  • Rebuild v/s Refactor v/s Re-Architect dilemma
  • Incremental modernization v/s one time modernization dilemma
  • Complex Business portfolios
  • Performance and scalability
  • Risk mitigation

Modernization Approaches: "Let us gear up and start the modernization, it is high time

There are 3 major approaches described below for legacy modernization. Organizations can choose anyone based on their business requirement.

  • Replace- Replacement of existing legacy systems (100% Modernization i.e Rewrite from the scratch)
  • Maintain- Enhance and Improve existing legacy systems (Make it maintainable with less effort and cost)
  • Phased Replace - Incremental/slow modernization (One-at-a-time approach, modernize it gradually)ModernApprpaches_3.png


Replacement of existing legacy systems (100% Modernization)

  • Replace with COTS approach
  • Custom Re-Write Development approach

Description: In this approach the entire legacy system would be rebuilt /re-architected/replaced with the latest cutting edge tech technologies and platforms e.g. J2EE, .Net, Cloud, Oracle, Salesforce, Pega, Digital etc. Old legacy system will be decommissioned soon. Built from the scratch is the fundamental goal of this option. This approach requires huge effort and cost with longer duration for target modernized To-Be systems. Big enterprises should adopt this approach considering they have surplus IT budgets with backup systems for serving their existing customer needs. High risk is involved in this approach hence long term business vision plus solid strategic is required for planning and successful execution. Modernization business plan must consider failover (risk mitigation) strategy before implementation. End-to-end insurance policy administration and claim systems replaced with a new claims systems is one of the example for such a modernization. Over here we can choose a COTS product (e.g. GuideWire, Duck Creek) or go for custom implementation based on business requirements. As a business benefit this option would certainly provide the highest return and best competitive edge over other industry leaders running the same business. Target state modernized To-BE systems will be future ready. Successful implementation will receive a huge boost in terms of operational efficiency and SLA adherence for critical business processes. Modernization scope is almost 80-90% in this option.

Ideal Duration: 2-5 Years

Some Technology COTS Options for Replace

  • GuideWire or Duck Creek- Property and Casualty Core Platforms for Insurance ( For Insurance Organization) 
  • AWS, Azure, Bluemix, Google, Oracle Cloud , PCF- Cloud platforms
  • Salesforce, SAP, Pega, Microsoft, IBM - Platforms for end to end business services        


Let us maintain and enhance existing legacy systems. 

  • Continue using as is legacy systems with bare minimum changes
  • Enhance Non-mission critical business components (e.g. Enhance UI Layer/Customer Portals/ Dashboard/Presentation layer etc.)
  • Focus would be on reuse principal with minimal changes based on identification of services which needs to be modernized (~20%)
  • Do not modernize or migrate critical business processes and components (e.g. Business Rules, Premium calculation services, Transactional services, confidential secure data services etc.)

Description: In this approach focus would be just to maintain existing legacy systems with minimal changes to avoid risk and failure. It is a low cost and risk free approach which satisfies partial modernization objective of the organization. In this approach core business services and critical business components would not be impacted however we can write a wrapper on top of existing core services or expose some of the business services securely so that we could reuse it for different modernization purposes e.g. (data visualization, reporting, decision making, portal services etc.). This approach is recommended for small to middle scale organization with less IT budget and less risk taking capabilities. Enhancing front end, creating dashboards, portals, onboarding a 3rd party library for optimization, creating a web user interface etc. are the major go-to activities in this option. Best part of this option is the extension which we use to get for existing legacy application rather than immediately replace it with future ready technologies. It can be adopted as a cost saver option. Modernization scope is almost 20-30% in this option.

 Ideal Duration:  0.5 - 1.5 years  

Phased Replace (Incremental modernization)

  • Let us transform and modernize legacy systems in incremental manner
  • It is a slow phase-wised replacement approach works based on "one at a time" principal. 
  • This modernization approach identifies loosely coupled components of the existing legacy IT systems and replace it with the appropriate equivalent newer IT technology component as an independent modernized business component and deploy them into production environment to check their fitment while rest of the other business components still uses same older legacy technology. After successful migration of 1st component other business components also transformed and replaced in incremental manner. 

Description: In this approach entire legacy system would be divided into multiple logical group of business components and then replace them phase wise without even touching the other business components. In a typical enterprise application scenarios "phased replace" approach also known as "layer wise modernization" where at a time one layer use to be consider for modernization. (E.g. Presentation layer, Enterprise layer, data access layer). Automated migration using tools from legacy to modern technologies is also considered in this approach as it is an independent route for legacy modernization.

It is quite safer and popular approach among middle level organization because of less cost and quick time to market. This approach also has less amount of risk involved because at a time we consider only one layer or one independent business component for modernization with a solid rollback strategy. It is a most recommended approach for business where only a few business components contribute to most of the major issues. Modernization scope is almost 50-60% in this option. 

Some examples below 

  • Business rules component modernization
  • Developing an independent service wrapper for accessing existing business services 
  • Adding a new independent enterprise service bus (ESB) component for orchestration
  • Modernize database from a legacy flat file store to RDBMS/ DDBMS/NoSQL storage systems.
  • Modernize existing legacy batch jobs to a real time online environment 
  •          e.g. legacy IBM AS400 batch -->  Spring Batch/Spring Boot modernization
  • Modernize a small legacy green screen UI  --> Intuitive UI 
  • Add a new dashboard/reporting components on existing legacy systems
  • Migration of legacy programming languages to modern languages using automated tools
  • Save annual license cost by replacing it with an open source component , examples below
  •          WebLogic/Websphere  --> Jboss/Tomcat (Application server)
  •          IBM data power --> Jboss Fuse (ESB Platform)
  •          FileNet --> Alfresco (ECM Platform)
  •          JSP/ASP/JSF --> Angular, React, NodeJS ( Web framework) 

Ideal Duration:  1 - 2 years  

Paradigm shift before and after legacy modernization 

Below diagrams shows radical changes before and after the modernization journey. Transformed modernized system would be future ready.


Top Technology Platforms for Modernization 

Let us choose appropriate technology platform for transformation. We can choose either COTS product or open source platform for custom development.  Some of the major platforms are available below. 



Selecting an appropriate strategy for legacy modernization is imperative to the real success of an enterprise's modernization implementation journey. Organization vision along with CIO's strong decision making capability in terms of right timings, Surplus IT Budget, Skilled IT staff, Cost effective optimal solution. Modernization strategy along with challenges, 3 major approaches and technology platform detailed in this article will help the businesses. Most of the big players have already completed this transformation while other small-sized and mid-sized organizations are in progress. It has become oxygen for enterprises which is must for survival in this competitive era hence sooner or later everyone has to plan for this transformation. Time has come to say good bye to our legacy systems. Let us gear up , choose appropriate modernization option , assess your business needs and initaite the modernization.

Authored by: Jitendra Jain
Senior Technology Architect, Infosys

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