Re-engineering legacy software focuses on extending its functionality, eliminating bugs, and improving performance. In this way, re-engineering can be perceived as a process of constant improvement that aims at meeting existing and emerging market needs. However, embarking on a journey to adopt new technology and improve quality and maintainability of the product should be an informed decision. The goal of this article is to be a guiding beacon for companies that are considering re-engineering and want to piece together all the elements of the process.
Based on my 17 years of experience in software development and modernization, I’ll explain what re-engineering is and which techniques and best practices to leverage to gain the best results from its use.
Defining Re-engineering and Its Benefits
Re-engineering is a software modernization technique that involves analysis, design, and modification of an existing software system to reconstitute it in a new form. The process boils down to upgrading or migrating a system to a more advanced platform.
Re-engineering aims at modifying the existing system to improve or reuse it as a new product. The primary goal is to make the solution more efficient, scalable, and adaptable. This involves improving system performance, increasing reliability, reducing maintenance costs, and ensuring the system can meet current and future business requirements.
Let’s take a look at the benefits that make reengineering look appealing to businesses.
- Optimized feature set and simplified application design
By refining the software, re-engineering simplifies the overall application design and optimizes the feature set, making the solution more user-friendly and efficient.
- Performance improvement by optimizing code
Optimizing the code base leads to significant performance improvements, resulting in faster and more reliable system operations.
- Process continuity
Well-documented and re-engineered systems ensure process continuity, minimizing disruptions even if there is staff turnover.
- Ability to leverage modern technology
Re-engineering allows businesses to integrate and leverage the latest technologies, ensuring their software remains current and competitive. For example, you might implement different integrations or AI-powered features.
- Cost and risk reduction
Compared to developing new software from scratch, re-engineering is usually more cost-effective and carries lower risks, making it a safer investment. In this case, the cost reduction is achieved through eliminating any non-value-added activities and features.
- Ability to add useful features and seize new opportunities
Modernizing application makes it more adaptable, allowing for the easy addition of new features and the ability to leverage new market opportunities. For example, it’s possible to implement integration with AI, ML, cloud, and analytics and reporting modules.
3 Key Signs You Might Need Software Re-engineering
Recognizing the signs that indicate the need for software re-engineering is crucial for maintaining an efficient, reliable, and modern software system. Here are three key indicators that it might be time to consider re-engineering your software:
- Legacy system compatibility issues
- Performance and scalability limitations
- High maintenance costs and frequent failures
Legacy system compatibility issues
One of the clearest signs that your software may need re-engineering is when it becomes outdated or incompatible with modern technologies. Legacy systems, built on outdated platforms or using obsolete programming languages, often struggles to integrate with newer systems and may have an inconvenient user interface. If your software faces challenges such as these, it becomes essential to update the system.
Performance and scalability limitations
As businesses grow and user demands increase, software systems must handle larger workloads and scale effectively. Struggling to meet performance requirements or a lack of scalability can significantly hamper business operations. Re-engineering can optimize your software architecture, improve algorithms, and enhance resource management, resulting in better performance and scalability.
High maintenance costs and frequent failures
Legacy systems often incur high maintenance costs and require extensive effort to support due to their outdated infrastructure, complex codebase, and lack of vendor support. If your software demands frequent fixes, patches, and updates, leading to unsustainable maintenance costs, it is a clear sign that re-engineering is necessary.
Working with experienced software consultants is vital in accurately assessing whether your software needs re-engineering. The MobiDev team can bring the expertise required to evaluate your current system, understand your business goals, and recommend the best course of action to ensure your software remains efficient, reliable, and aligned with your strategic objectives.
Legacy Software Re-engineering vs. Other Software Modernization Approaches
When a business decides to modernize its software application, there are generally three approaches to address the problem:
- Rehosting/Replatforming
- Re-engineering
- Rebuilding
Rehosting/Replatforming
Rehosting or replatforming is moving the application “as-is” to a more modern environment, such as migration from on-premises to the cloud or new hardware. It is beneficial when company resources are limited, and the code is relatively well-built. For example, migrating from .NET Framework to .NET Core involves well-defined steps without a total system overhaul.
The benefits of rehosting are minimal changes to the code, sustainability of core features, and moderate resources and expertise required for prompt execution. The rehosting drawbacks may include potential porting code errors and legacy components to the new system, limited ability to adjust the software to specific needs, and difficulty in expanding functionality.
Re-engineering
Re-engineering is rewriting the app in a new form using existing old components. This approach focuses on improving the technology itself by modifying the software architecture or code structure and refactoring problematic code pieces. It requires highly skilled engineers and a software architect for the project. Re-engineering is used when the codebase is imperfect, and the team can justify the benefits of new technologies for the enterprise.
Advantages of re-engineering are increased performance, code transparency and predictability, overall software enhancement, and reduced maintenance costs. At the same time, re-engineering requires a dedicated team familiar with the system and may be associated with some risks. For instance, lack of documentation can lead to poor programming decisions.
Rebuilding
In contrast to re-engineering, rebuilding is rewriting software from scratch. It starts from rethinking business requirements, redocumenting, and rewriting the application. This does not mean rewriting the entire application at once but incrementally over time. This approach is suitable for extremely problematic projects with no technical or business documentation, no original developers, and no robust software architecture.
The benefits of rebuilding are significant changes and the introduction of new features, revision of project goals and business processes, and future-proof solutions.
Challenges include large upfront costs, complex procedures requiring expertise and a reputable software modernization vendor, and a high-risk approach. Find below a brief comparison of these software modernization approaches.
| # | Strategy | Examples | Advantages | Features |
|---|---|---|---|---|
| 1 | Rehosting/Replatforming | Migrating a legacy application to a cloud platform | Cost-effective, minimal changes, quick deployment | Enhanced scalability, improved performance, minimal disruption |
| 2 | Re-engineering | Refactoring a monolithic application into microservices | Improved flexibility, easier maintenance, better scalability | Modular architecture, enhanced fault tolerance, easier updates |
| 3 | Rebuilding | Creating a new version of an old software from scratch | Modern features, optimized performance, future-proofing | Latest technology stack, modern UI/UX, enhanced security |
A brief comparison of software modernization approaches
Software Re-engineering Techniques
Software re-engineering encompasses several critical techniques designed to address the challenges posed by legacy systems, enhancing their performance, maintainability, and adaptability. These techniques include reverse engineering, restructuring, modularization, and covering. Let’s explore each of these techniques in detail.
Reverse Engineering
Reverse engineering is the process of dissecting an existing software system to understand its components, structure, and underlying design. The aim is to develop a high-level, abstract representation of the system, such as architectural diagrams, data models, or behavioral models. This technique is essential for comprehending legacy systems and serves as the foundation for further re-engineering efforts.
Reverse engineering involves analyzing the source code to identify its structure and dependencies, conducting both static and dynamic program analysis to understand its behavior, and extracting data from existing system artifacts to create comprehensive models. This approach is particularly useful when assessing the feasibility of future changes, facilitating smoother substitutions, predicting the impacts of enhancements, shortening the learning curve for new support providers, and identifying reusable components for future integrations.
Restructuring
Restructuring, also known as application refactoring, involves altering the internal structure of a software system without changing its external behavior. The primary objectives are to enhance the system’s maintainability, flexibility, and performance.
Techniques used in restructuring include code refactoring to simplify complex control structures, improve naming conventions, and remove redundant code, data structure transformation to enhance efficiency and readability, and program slicing to break down the program into smaller, manageable pieces.
Modularization
Modularization is the process of breaking down a software system into smaller, more manageable components or modules, aiming to enhance the system’s modularity. This refers to the degree of independence and isolation between the system’s components.
Techniques used in modularization include identifying functional units to break down the software into distinct areas, defining appropriate interfaces for communication between modules, and organizing system architecture into loosely coupled modules.
Covering
Covering, also known as coverage analysis, involves determining the extent to which the existing software system is covered by various software engineering activities, such as testing, documentation, and traceability.
Techniques used in covering include code coverage analysis to assess the extent to which the codebase is covered by tests, requirements coverage analysis to ensure that all requirements are addressed by the software, and test coverage analysis to measure the effectiveness and thoroughness of the testing process.
Covering is crucial for enabling web and mobile experiences, allowing the reuse of the application’s functionality by external systems, and integrating legacy systems with modern technologies through REST/SOAP APIs and mobile-ready interfaces.
Although updating legacy software brings numerous benefits to companies, any re-engineering technique, from reverse engineering to covering, may be associated with іsome challenges. Awareness of these challenges and the ability to address them allows companies to manage the risks and successfully modernize their legacy systems.
Addressing the Challenges of Re-engineering Legacy Software
Re-engineering legacy software requires a combination of technical expertise, strategic planning, and effective communication to navigate its complexities and achieve successful outcomes. Let’s dive into the possible challenges and how you can mitigate them.
1. Understanding legacy systems
Older software often has complex, undocumented architectures and code bases, making it difficult to comprehend the existing system and its behavior, especially if the original developers are no longer available. Experienced engineers can mitigate this by using reverse engineering techniques to analyze and document the system and engaging knowledgeable staff or original developers to aid this process.
2. Extracting and preserving functionality
Missing or incomplete requirements can lead to functionality gaps in the new system. Conducting thorough requirements gathering and stakeholder interviews and using automated tools to ensure all functionalities are mapped and preserved can address this issue.
3. Technical debt
Legacy systems often have accumulated significant technical debt over time, such as outdated technologies, poor code quality, and suboptimal design decisions. Addressing this technical debt during the re-engineering process can be complex and time-consuming. Refactoring services and cleaning up technical debt can be resource-intensive, but implementing code restructuring and modularization techniques and prioritizing critical areas can help address technical debt incrementally.
4. Maintaining system availability during re-engineering
The existing system needs to remain operational with minimal disruption to end-users. This requires careful planning and coordination to ensure a smooth transition to the new system. To balance re-engineering activities with ongoing operational requirements, it is important to plan and execute in phases to minimize downtime and use parallel systems or staging environments to ensure continuity.
5. Integrating with new technologies
Re-engineered systems often need to integrate with modern technologies, such as cloud platforms, microservices, and APIs. Leveraging expertise in modern technologies and integration patterns and using modularization and interface wrapping can facilitate smooth integration.
6. Validating and testing the re-engineered system
It’s critical to ensure the re-engineered system behaves identically to the legacy one or improves upon it. Developing detailed test plans and using automated testing tools, along with rigorous regression testing, can help verify functionality more efficiently.
7. Organizational and cultural challenges
Resistance to change, lack of buy-in from stakeholders, and difficulties aligning with the organization’s overall strategic goals are common issues. Engaging stakeholders early and often, clearly communicating the benefits and goals of re-engineering, and aligning the project with strategic objectives can help mitigate these challenges.
8. Project management and scheduling
Unpredictable timelines and costs due to inherent complexities require effective project management and realistic scheduling. Working with experienced project managers and agile methodologies, setting realistic milestones, and continuously monitoring progress can help manage these aspects effectively.
Best strategies to mitigate the challenges
- Use reverse engineering techniques and engage knowledgeable teams
- Conduct thorough requirements gathering and use automated tools
- Implement code restructuring and modularization techniques
- Plan and execute in phases, use parallel systems or staging environments
- Leverage expertise in modern technologies and integration patterns
- Develop detailed test plans, use automated testing tools, perform regression testing
- Engage stakeholders early, communicate benefits and goals, align with strategic objectives
- Use experienced project managers, agile methodologies, set realistic milestones, monitor progress
Software Re-engineering Process Step-by-Step
Software re-engineering is a methodical process that involves several critical steps, each tailored to address the unique needs and challenges of specific projects. Here is a general flow that can be adapted to meet the requirements of various re-engineering efforts:
- Initial Assessment and Planning The initial phase involves identifying the objectives of the re-engineering project, such as improving performance, enhancing maintainability, or integrating new technologies. A feasibility study is conducted to understand the scope, potential benefits, and risks involved. Stakeholder engagement is crucial at this stage, gathering input from end-users, business analysts, and IT staff to ensure alignment with business goals.
- Reverse Engineering The next step is reverse engineering, where the existing codebase and system architecture are examined to identify components, dependencies, and interrelationships. This phase also involves restoring lost or outdated documentation by analyzing the source code, interviewing original developers if available, and reviewing system artifacts. Understanding the system’s current functionality through static and dynamic analysis techniques is essential.
- System Restructuring System restructuring follows, focusing on improving the internal structure of the code without altering its external behavior. This includes simplifying complex control structures, removing redundant code, and enhancing naming conventions. Additionally, data structures are optimized to improve efficiency and readability, and performance tuning is conducted to optimize algorithms and data access patterns.
- Modularization In the modularization phase, the system is decomposed into smaller, manageable modules based on functionality. Clear interfaces are defined for each module to promote loose coupling and high cohesion, and functionality is encapsulated within modules to improve maintainability and facilitate future enhancements.
- System Integration and Covering System integration involves developing APIs to enable integration with modern systems and technologies, such as cloud platforms and microservices. The user interface is modernized to improve user experience and accessibility, ensuring it meets contemporary standards and practices. Comprehensive testing is ensured by analyzing code coverage, requirements coverage, and the effectiveness of test cases.
- Validation and Testing Validation and testing are critical to verify that the re-engineered system maintains all original functionalities and meets new requirements. This includes functional testing to verify functionality, performance testing to ensure the system meets specified benchmarks, and user acceptance testing (UAT) to involve end-users in validating that the system meets their needs and expectations.
- Implementation and Deployment The final phase involves phased deployment, gradually deploying the re-engineered system in stages to minimize disruption and gather user feedback. Training and support are provided for users and support staff to ensure a smooth transition, and continuous monitoring and maintenance are conducted to identify and resolve issues promptly.
This general flow can be adapted to the needs of specific projects, ensuring that each step aligns with the unique requirements and challenges of the re-engineering effort. By following these steps, organizations can effectively modernize their software systems, ensuring they remain functional, efficient, and aligned with current and future business needs.
Best Practices for Application Re-engineering
To make re-engineering projects succeed, consider using the following best practices:
1. Comprehensive Assessment and Planning
Make sure to conduct a thorough assessment to evaluate the existing system’s architecture, functionalities, and dependencies. This helps identify areas needing improvement and determines the feasibility of re-engineering efforts. Setting clear objectives is crucial; these should be specific and measurable to align with business needs and strategic goals. Engaging stakeholders, including business analysts, end-users, and IT staff, ensures that their needs are addressed and incorporated into the project.
2. Leverage Automation Tools
Utilizing automated tools for code analysis, refactoring, and testing can increase efficiency and reduce human error. These tools are particularly useful in reverse engineering, restructuring, and validating the system. Implementing continuous integration and deployment (CI/CD) pipelines facilitates smooth transitions, frequent testing, and faster deployments, ensuring a streamlined process.
3. Focus on Modularization
Breaking down the legacy system into smaller, manageable modules improves maintainability and scalability. Each module should have a well-defined interface and encapsulated functionality. Promoting reusability by designing modules that can be used across different parts of the application or in other projects reduces redundancy and enhances consistency.
4. Ensure Robust Documentation
Maintaining comprehensive and up-to-date documentation throughout the re-engineering process is vital. This includes design documents, code comments, and user manuals to facilitate future maintenance and knowledge transfer. Documenting architectural and design decisions provides context and rationale for future reference, ensuring that all changes are well-understood and traceable.
5. Implement Rigorous Testing
Automated testing frameworks should be utilized to ensure thorough and consistent testing of the re-engineered system, including unit tests, integration tests, and system tests. Performing user acceptance testing (UAT) with end-users validates that the re-engineered system meets their needs and expectations, ensuring a user-centered approach to quality assurance.
6. Adopt Agile Methodologies
Iterative development using agile methodologies allows for continuous feedback, rapid adaptation to changes, and incremental delivery of improvements. Frequent communication with stakeholders and team members ensures alignment and prompt issue resolution, maintaining project momentum and clarity.
7. Manage Risks Effectively
Conducting a risk assessment helps identify potential challenges and develop mitigation strategies. This includes managing technical debt, ensuring system availability, and addressing integration challenges. Continuously monitoring the progress of the re-engineering project ensures it stays on track and meets predefined goals and timelines, allowing for proactive adjustments as needed.
By adhering to these best practices, you can effectively navigate the complexities of application re-engineering and achieve successful outcomes that align with their strategic objectives.
Re-engineering Success Stories from MobiDev’s Experience
The MobiDev team has led dozens of successful re-engineering projects. In this section, we will share the most prominent use cases so that you can better understand what benefits competent re-engineering may offer to businesses.
Success Story #1: Modernizing a Bank Management System
Background
A multi-tenant Ruby on Rails startup was facing significant issues, including slow response times under load, increased development times for new features, a single point of failure, and inadequate security mechanisms. Provided Software Audit services revealed that the monolithic architecture of the application was a primary barrier to scaling.
MobiDev proposed a plan to optimize the codebase, transition to a microservices architecture, and migrate to a new cloud infrastructure. The implementation involved augmenting the client’s team with our engineers and architects to bridge the expertise gap and provide technical oversight.
Challenges
- Significant load from periodic computations
- Quality sacrificed for speed in early development stages
- Difficult-to-extend and maintain codebase
- Slow tests impeding development and release processes
- Hard dependencies between system components
How we delivered
- Provided cloud migration services from AWS to Azure, using Single Sign-On (SSO) and Azure Active Directory (AAD)
- Improved architecture and legacy codebase to restructure the app into microservices and separate the frontend
Business Outcomes
- Enhanced scalability and performance to handle high computational loads and demand spikes
- Improved maintainability, extensibility, and reduced technical debt through better code quality
- Accelerated feature development and easier adaptation to changing business requirements
- Increased market competitiveness and reduced operational costs
Success Story #2: Upgrading a legacy app with new technologies
Background
A startup social network for teams, initially developed on WordPress, aimed to introduce a growth management tool using Ruby on Rails. However, managing multiple technology stacks (WordPress and RoR) proved challenging, slowing down development.
The client lacked expertise in developing new services on Rails, so MobiDev stepped in to provide a full-cycle development team.
How we delivered
- Rewrote the WordPress part of the project using RoR to unify the technology stack
- Introduced microservices architecture to isolate multiple apps from each other while allowing data sharing (e.g., user data), improving overall stability and performance
- Implemented CI/CD automation to reduce release risks and streamline the development process
Business outcomes
- Improved efficiency with reduced maintenance overhead
- Eliminated compatibility issues
- Enhanced scalability and performance
- More reliable system that can handle increasing user loads, data volumes, and computational demands without compromising performance
- Improved resource utilization and simplified scaling efforts
- Better customer experience
How MobiDev Software Re-engineering Services Can Help You Succeed
Since 2009, MobiDev has been building, scaling, and modernizing software products. Our extensive experience spans various industries and project complexities, making us a reliable assistant for your software re-engineering needs.
MobiDev boasts a team of in-house consultants and engineers who are proficient in auditing your software and existing infrastructure. We create comprehensive re-engineering strategies tailored to your unique needs and execute them successfully, ensuring minimal disruption to your operations.
Let us help you unlock the full potential of your legacy systems and achieve your business goals! Learn more about our software modernization services or contact us.
