3 Legacy Software Modernization Case Studies and 12 Lessons We’ve Learned
According to a recent survey, businesses that fail to modernize their software systems run the risk of losing up to $1.8 trillion in productivity.
Although software modernization works, it can be complex and costly. That’s why it helps to learn from some of the successful legacy system modernization case studies.
This article discusses 3 legacy system modernization success stories of our valuable clients and the lessons learned.
Case Study #1 Upgrading AngularJS to Angular 11 for an Enterprise-wide Web Platform
A premium provider of information technology and financial services in the healthcare industry experienced bottlenecks with their multiple module system built on AngularJS. They sought to migrate from AngularJS to Angular 11 to overcome these challenges.
Major challenges encountered during migration and our solutions
- Dealing with complex functionality and architecture: Since the architectural patterns in AngularJS and Angular are completely different, our team aligned the business logic of the solution with the target system.
- Selecting proper substitutes for legacy AngularJS tools: We carefully chose libraries to facilitate further maintenance on the new Angular 11 system.
- Efficient management of user resistance to the new designs: We devised a plan to boost user acceptance towards the new look of the application.
- Data transfer was the second-hardest task: This is one of the many disadvantages of legacy systems – moving data to better infrastructure. Our team took an incremental approach to migrate data that eliminated disruptions and operational interruptions.
The results
The client received a quality product, complete documentation, and a streamlined software structure. They gained a higher ROI with improved performance, and credits to the new on-time system. Maintenance costs were reduced as bugs and errors can now be resolved much faster and with less effort.



The project, which is still ongoing, taught us the following lessons
Lesson 1 Frameworks with the same roots can be utterly different; thus, they must be approached differently
AngularJS and Angular 11 are completely different, so the frameworks require different approaches, and the upgrade wizards won’t help. Approximately half of your application’s codebase must be rewritten from scratch to ensure a smooth transition.
Lesson 2 Redesign the app in parallel if users and business context require it
The new solution’s frontend might require a few UX changes by a developer during the migration.


How to do a legacy system redesign the right way? Read here. Risks and Approaches of Legacy Application UI/UX Modernization
Lesson 3 Don’t be afraid to rewrite the app’s parts or the whole app piece by piece
If rewriting is carefully planned and done right, the new solution will fit your budget, meet deadlines, and maximize the ROI.
Lesson 4 Consultation with a professional software modernization company ensures successful migration
Switching from AngularJS to Angular is complicated, so do it with an expert legacy systems modernization vendor. A proper consultation will save you money and reduce the development time.
Read the full version of the case study on AngularJS.
Case Study #2: Migrating .NET Framework 4.7 Backend of the Large-scale Enterprise System to .NET Core 3.2
For this legacy software modernization case study, we helped our client, a key player in the US healthcare market, achieve a successful .NET Framework to .NET Core migration.
Major challenges encountered during migration and our solutions
- Recreating the functionality of the target system: During the migration, our team rewrote some parts to save the initial system’s structure.
- Selecting proper substitutes for the missing .NET Framework libraries: Most third-party controls and libraries of the .NET can’t be ported to .NET Core. So, we had to manually choose the needed libraries and controls.
- Implementing new features on the go: The business needs kept changing throughout modernization, forcing our team to work on the new functionalities concurrently.
The results
This 6 months project allowed us to provide an improved application to our clients, with more opportunities for users. First, in contrast to .NET Framework limitations, .NET Core lets the system run smoothly on Mac, Linux, and Windows. With the new .NET standard libraries, their dev team can now implement crucial features much faster in different environments at once.



Lessons we learned from this migration
Lesson 5 Refactor, refactor, and refactor again
Refactor code until you can’t. By legacy code refactoring, we enhanced the structure, design and implementation of the program. This, in turn, minimizes complexities and improves code readability and maintainability.
Lesson 6 Plan the migration in advance
Start making plans to upgrade your application and invest in solid documentation because the lack of it becomes the biggest obstacle to modernizing outdated applications.


Creating the app modernization roadmap can put your project on the rails. Creation of Effective App Modernization Roadmap: Everything You Need to Know
Lesson 7 Thoroughly choose the proper substitutes for the existing app’s libraries and components
Even straightforward migration projects might fail. You need to replace existing app libraries with compatible ones; you don’t choose randomly. Select elements according to the system’s functionality and the initial structure.
Lesson 8 Avoid possible pitfalls during the migration from the very beginning
There are many pitfalls for software migration projects, and the one thing you can do here is to follow industry best practices. Starting with frequent system audits to be in the loop of any issues, learning about tech updates (and we know the best place to look for them – ModLogix blog), and working with a trustworthy legacy software modernization company.
Read more details about .NET migration and its peculiarities.
Case Study #3 Cloud Migration from ASP.NET Webforms to Microsoft Azure
Our client is a scalable clinical trials database registry for this case study.
Major challenges encountered during migration and our solutions
- System environment parameters: Moving the system to the cloud could cause malfunction and security concerns. To solve this issue, our team built a development environment in the cloud and rewrote some app parts to make them compatible.
- Database compatibility: The MS SQL database used in the current system needed upgrades and fixes because it wasn’t Azure SQL compliant. We solved these challenges by building an ASP.NET app for inserting into the Azure SQL database.
- Unsupported parts: Azure Firewall was incompatible with the current solution – flagging several harmless requests as potential threats that could stop the whole system’s work. To mitigate this, our team replaced the Azure Firewall with Cloudflare Firewall, which allowed specific requests.
The results
With this 4 months project, we delivered a modern application that offered 200 times faster report building, 99,99% guaranteed business continuity, and 297 code issues fixed. Our expertise in mobile development allowed us to build a biometric authentication app.



The project allowed us to learn the following lessons
Lesson 9 Calculate the cost of cloud migration beforehand
In order to meet the budget, you need to be aware of all the upcoming costs – pre-migration, cloud, migration, as well as post-migration costs. List everything to avoid unpleasant surprises.


What should you pay attention to when estimating the cloud migration. How to Estimate the Cost of Cloud Migration
Lesson 10 Understand your workloads before selecting a cloud model
The amount of workload that your business deals with affects the cloud model that you should opt for. Consider elements like request size, web page load time, and time zones.
Lesson 11 Pay attention to the solution architecture in the cloud
Work with Data architects to implement several best practices when planning, building and maximizing the benefits of a cloud data architecture. Adopt metrics to assess how cloud services can minimize the cycle time of data analytics applications.
Lesson 12 Adopt a comprehensive approach to development
It is important to choose the most suitable method among legacy software modernization approaches to meet all of your project needs.
Discover more about this legacy to cloud migration project.
Final Thoughts
The above case studies in legacy system modernization affirm that with the right technical partner, every business can achieve successful software modernization, to benefit from that boost in ROI, reduction in costs, and improved performance.
Browse our site to discover more examples of legacy modernization.
Take the first step towards your modernization journey. Schedule a free consultation session with ModLogix today to get started.