How to migrate a legacy system to a new UI?

Code on computer

What is a legacy system? Most of the time it refers to a system or systems that cannot be changed to newer formats or its applications cannot be promptly updated. 

Being a crucial part of the company’s daily life, the legacy system always encompasses a variety of systems such as servers, operational systems, ERPs, CRMs, financial applications, web portals, etc. All of these systems may be hard to operate, and thus they need to be modernized. 

Complete modernization is not the only choice for companies, as long as it takes a lot of time and material resources. Some companies are trying to combine new technologies with existing ones, implement new cutting-edge solutions (Blockchain, AI, Machine Learning), or modernize their technical part step-by-step to keep the whole system functional.  

Reasons to migrate

To make your company competitive in a market, it’s important to have agile technologies adopted. Such implementation helps your company overcome the most common obstacles for business development.

High maintenance cost

The legacy systems are getting harder to maintain in terms of money and time. Companies are wasting money on running an inoperable system when it is much profitable to take advantage of adopting new technologies. 

Security concerns

Data breaches and cyberattacks are common things for legacy systems. Newer systems offer higher protection to customer data and thus provide wider trust and build a good reputation for a company.

Slow performance

The performance of such systems is tremendously slow when high efficiency is the key pillar for most companies. Your business should be flexible and agile to deliver more for fewer resources used. Outdated technology is the reason for the failure to adapt to the constantly changing market.

Harder compliance

It’s hard for most legacy systems to meet security standards. For example, such a standard as GDPR requires a company to know what kind of customer data they operate, where this data is, and who can access it. 

Poor integration opportunity

To operate efficiently, the company must have an opportunity to integrate with systems. For instance, if you want to add live chat based on Artificial Intelligence, it’s almost impossible to implement it painlessly. Although some integration is still possible, it requires sufficient time and money to bring it to life without breaking the whole system. 

Types of migration

Not all companies can afford the at-once system modernization due to high time & money spending.  They are built on decade technologies and huge alterations can result in loss of company development. There are five ways to modernize the company’s functionality, and each of them should be decided on a case-by-case basis.

Total modernization

This type of migration allows building a new system from scratch using new technologies stack. When the system can’t implement necessary changes to compete in the market, or it’s too expensive to support the old one, a complete transformation is a must. It entails many benefits for a company, from high competitiveness to flexibility to changes.

Gradual replacement

If you aren’t ready to risk and change the system at once, you can start replacing your system piece by piece (i.e., web portal or CRM rebuilding). It works when the company is short on time & money and consumes less management than during a total transformation. At the same time, the different applications can be built using different technologies and thus be amalgamated.

Quick fix

In the case of emergencies, a tapping fix can be used to address small problems (to change a part of the application functionality). It’s built using new technologies while old ones prevail. A low budget is enough to bring changes to life. However, such a transformation can lead to bad design and become a throwaway work if done without proper management.  

Existing system improvement

Applications may contain dead code that needs to be removed, or there may be situations when parts of the existing code should be fixed. No need to change the technology, however, the scarcity of experts may lead to quality issues. 

No system change

Insufficient funds, lack of tech knowledge, indecisiveness, or other reasons stop the company from developing. Unless the transformation plan is created, following this approach may be harmful over time. 

The process of migration


Once the company understood that migration to a new UI  can become a solution to many operational issues, it requires a deep analysis of the whole migration process. If you don’t have a reliable company, who can help you migrate, then it’s the proper time to find one. Make sure the company has experts who work with legacy systems and can clearly understand the old code. 

Migration requires a precise understanding of what should be migrated. Determine what functionality you want, what kind of problems you have with old functionality,  who will use it, and how you want it to work. These steps are required if you want to be understood and receive the product needed. 

Process determination

Mutual understanding is key to a successful product. The process of pre-development and development communication is divided into interviews and call, where the Product Owner (PO) and Project Manager (PM) define the product requirements. To build the right product, the development company must understand the pains of the company’s old product they used, requirements, and results expected. The key point of the migration process is to move the legacy system to a new UI without destroying the existing patterns of the product and add new ones to accelerate the company’s efficiency. 

When the interview is conducted, the Project Manager is working out a technical assignment for a UI / UX designer. The designer creates mockups that should be firstly approved by the Product Owner to proceed to the development stage. 

At this stage, the development company provides you with prior time & budget estimation.  


The development process strictly follows the technical assignment approved by the Product Owner. The process consists of iterations (typically, 1- or 2-week long), at the end of which the team is presenting the result achieved during the iteration. 

Thanks to the agile development principle, the Product Owner is tracking the whole process and can modify the requirements during the iterations.

Advantages and Disadvantages (Comparable table)

Before After
Money $: lack of money investment doesn’t allow the company to develop efficiently $$$: but a company is competitive in the market and is open to new opportunities
Time Time-consuming complex operational processes Operational processes time & budget reduced by 2-3 times
Tech Stack Out-dated technologies that result in talent scrutiny Modern cutting-edge technologies
Flexibility Difficult integration process and resistance to changes. Poor integration opportunity. Easy to integrate with less time & money resources
Compliance It’s harder and more expensive to meet worldwide security standards Total compliance with GDPR, HIPAA, and other standards
Security Difficulty in using new secured protocols that results in possible data breach Variety of secured protocols and processes according to the types of data collected. Ability to prevent cyberattacks.

To sum up

 The legacy system migration is definitely not an easy process. But you can alleviate it by knowing that you exactly want to be rebuilt and having the right company that can take care of all the development processes. 

If your company wants to succeed in the market but still uses outdated and complicated functionality in the day-to-day operation, then migration help to reduce operational time & costs. It takes time and money, but the result is bigger than all the efforts invested.