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Legacy System Migration – Challenges, Strategy

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Every software has its expiration date. Time goes by, and technologies evolve, bringing new standards, and approaches, changing the average tech stack used by the majority of businesses. 

However, sometimes companies don’t catch this progress on time, and their existing systems become legacy applications: software pieces that still match their initial requirements, but are now utterly outdated. 

And though such software can still operate within its functionality, it might create additional issues with data transfer, integration with new software pieces, and many others.

For the business that owns legacy systems, the solution will be to initiate a legacy migration project. In this article, we will go through major aspects you should know about the legacy system migration process and how to get through this change with minimal damage to your day-to-day operations.

Why Do You Need Legacy System Migration?

Legacy system migration is a process that will demand a certain amount of time and effort, as well as an allocated budget. Hence, you should understand clearly why you need to initiate a migration project and how to explain its importance to your superiors and colleagues. 

The main reasons that drive businesses to migrate from legacy software are maintenance are:

  • the need to improve and redesign business processes related to the aforementioned system;
  • optimization of maintenance costs;
  • reinventing UX and making a software piece more intuitive and user-friendly.

Migration is not only about leaving behind outdated technologies, but about improving the way your existing system works. Flawed architecture, obsolete user interfaces, and redundant technical solutions might decrease the value the system might have brought to your business. 

It is a great chance to implement automation where it is possible or redesign flows, so it would take less time for users to complete their tasks. 

At the same time, legacy systems are expensive. They are usually written in old languages that are no longer widely supported or have a few specialists who can still work with them efficiently. Hence, transferring it to modern technology will save you IT budgets, as well as simplify the process of finding and hiring necessary tech experts.

Migration vs Modernization

Legacy system modernization and migration usually go hand in hand and complement one another. However, you might ask us a question: do we need to rewrite your system completely, or can we just update it and improve some precise parts? 

We would say that the decision depends a lot on the existing software and your business. Usually, we examine every case separately and choose how to approach it.

The truth is that every system can be improved, but not every need to be completely redone and transferred to new technologies. 

We suggest starting with evaluating your expectation from the system, use cases, and user experience, as well as running automated tests to check how the system is operating.

As a result, you might need to just modernize and redo user interfaces, or go through a much bigger amount of work and rewrite some parts of them.

Another important point here is scalability. Your legacy system might have worked correctly when it was used by fifty users, but what if you need to increase these volumes? If this growth wasn’t considered while writing the initial version of your software, you might need to dive deeply and reinvent it drastically. 

Main Challenges of Migrating Legacy Systems

The process of legacy system modernization and migration has its own pitfalls that can slow you down or increase the project cost if not handled right. So, you should know them, and together with your development team, think through the mitigation plans for each case.

Challenge #1: System Adoption

Your new system might drastically change from your old one. It is great news when we are discussing the current system’s functions, but it can be quite a challenge and disturbance for the system’s users, namely, your employees.

Getting used to a new system will be a hard process, as people need to relearn and adjust to the new system. To help them, you might schedule workshops or record videos explaining how to operate the updated system, so they would have guidance to feel comfortable transferring. 

Either way, you definitely need to explain the need for legacy system migration to your staff, so they would understand the reasoning and not consider the migration process as something meaningless.

Challenge #2: Requirements

Every legacy systems have requirements it should have met. However, you can just take them and reuse them in the form they were written previously.

Before starting the migration, you need to translate old requirements and features into the new system. It is especially important if you plan not only to change UI but to optimize business operations and reflect that into the updated software piece.

Challenge #3: Complexity of the Outdated Software

Another aspect you might struggle with is the complexity of your legacy system. As you can guess, migrating a system with a few screens would be easier than a massive system that unites dozens of features and massive amounts of data. 

However, careful assessment and planning will help you to structure your migration process and avoid major mistakes that might arise. 

Challenge #4: Data Migration

Data migration is one of the most concerning challenges for organizations and their decision-makers. Legacy systems that have been in use for years or even decades, might contain terabytes of important data. 

The question is how to transfer it without any data loss, as well as not to disrupt usual workflows significantly. There are different approaches: it can be done step by step, or everything will be migrated at once, or it can be handled on weekends when the staff doesn’t work.

Again, it varies for every project, as it has too many dependencies that will determine the best choice for successful data migration.

Legacy Migration Strategies

You might find different strategies for legacy application migration on the Internet. In turn, together with our development team, we decided to simply outline an action plan for the successful migration of a legacy system.

The main point you need to understand is that it is impossible to replace the legacy system in one go, especially if it has taken initially several years to develop it. Hence, the easiest way here is to do it part by part.

So, here are the main aspects you need to consider to power up efficient migration.

Previous Manuals

It is important to study the system itself before doing something with it. We usually request manuals, architecture, and other documentation to understand how the legacy systems work. 

If there is a lack of such data, we study the system and come up with such data ourselves.

Data Model

The data model explains how many components the system has and what entities they are, how big the system is, what dependencies we have, and what relationships there are.


As we have mentioned, most likely user interfaces are also outdated on legacy systems, so they need to be redesigned as well. We suggest talking with actual system users to understand how they used this system, figure out its value for clients, and come up with a design solution that will help users.

Business Analytics

The contribution of business analysts at this stage is essential. As we mentioned, we analyze previous requirements and documentation, and having access to them is a great advantage. However, it would be also beneficial to conduct interviews with people who work regularly with systems.


The last but not the least is to determine an approach for system migration and determine how you should start, for example, with some back-end component or with some use case that is the biggest pain for users.

Legacy System Migration with Altamira

Altamira, being a software development vendor for more than a decade, will be glad to run your legacy system migration.

Cooperating with us, you get access to:

  • strong development and delivery teams with specialists with years of experience in different niches and with different technologies;
  • a portfolio of success cases of software pieces developed for businesses;
  • custom approach to your project; we will study and assess your system to offer solutions that would be the most beneficial for you;
  • a client success team focused on delivering the best customer experience to you;
  • high ownership over the project;
  • flexible cooperation and payment terms.

What Specialists Do You Need for Legacy System Migration? 

To go through legacy system migration successfully, you would need a strong development team.

We are able to provide you with such team composition and cover all needs for legacy system migration at full capacity.

How Long Will It Take to Do a Legacy System Migration?

We can’t give you a general answer here, but we would be able to tell you this data when we have a chance to see your legacy system.

The timeline for system migration depends on different factors, namely:

  • team composition and experience;
  • size of the system;
  • third-party services the system is integrated with.

We choose an iterative approach and release an updated system gradually, so it won’t block your operations. 

In Conclusion 

Legacy system migration is a challenging process, but from a long-term perspective, it can be a great boost for your processes and IT infrastructure.

Choose a reliable tech partner to support you through the legacy system migration, and you will relieve yourself of dozens of possible complications.


The main challenges are data migration, updating requirements for new needs and priorities, its size, as well as its adoption by the staff who got used to a previous version of the software.
A legacy system is any type of software that is outdated. For example, if you are still using an ERP system developed in 2005, you are using legacy software.

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