How Legacy Code Migration Saves Your Bill

May 19, 2023
13 min

Legacy code migration is the process of moving your old software to a new cloud platform or rewriting your existing product on a new platform.

It is worth the investments as legacy software only takes lots of your time and funds without offering high performance to end-users.

Today, we want to cover this topic in great detail featuring:

  • Why you shouldn’t avoid legacy software migration
  • Why an IT system becomes a legacy system
  • How to migrate your old legacy software
  • How we got a 200x performance boost with a system migration.

What is Legacy Code Migration?

Put it simple, legacy code migration means taking the core components of your existing outdated software product or application and updating, reconfiguring it to run on modern technologies, tools, and systems.

In turn, a legacy system is an obsolete and outdated software built using old technologies and programming languages that are hard and expensive to maintain and support.

Legacy software migrations have two general options:

  • Movement of your entire outdated software to a new platform
  • Refactoring your legacy code on a new platform.


You need to choose the first option if the existing product functionality meets your business demands and end-users’ needs, but you still want to cut down maintenance and licensing costs, and boost performance.

The second option will become a great choice for your business if you also want to rewrite the existing product features, re-engineer the software architecture, and make significant changes.

It’s crucial for you to know that the legacy software migration strategy proposed by a technical provider should ensure the full operability of your entire system during the migration process.

At Ascendix, we always suggest to our clients the most cost-effective way of modernizing their legacy systems through making their platform work during the legacy system migration process, if possible.

The matter is that every case is unique and sometimes the legacy tech stack doesn’t allow us to migrate the system in parallel. But we always try to find technology solutions to optimize costs and minimize downtime for your business.

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Why an IT System Becomes a Legacy System

  1. Lack of required technical skills to support and upgrade the platform
  2. Long time no updates and legacy code audit
  3. Used system technologies become no longer supported


In short, an IT system becomes a legacy platform after approximately 10 years due to the lack of required developers in the market that can support, upgrade the platform, and because the legacy app no longer supports multiple tools and integrations that your business requires.

We want to cover the key indicators that mean your IT system has become outdated and needs legacy code migration shortly.


Maintenance costs of your current legacy software are much higher than supporting and scaling a modern solution

If your maintenance bill increases over time, it’s worth considering legacy code migration as supporting brand-new or modern software is much cheaper.


You see a significant decrease in IT system performance

A system performance decrease is also an indicator that your platform is becoming legacy and it needs modernization.


You face system upgrade and extend limitations

The more challenges you face while upgrading and extending your IT system, the more funds you will need to invest in the future to update and scale. So, we recommend considering legacy code migration if you start facing update and extend limitations.


It becomes hardly possible to handle many users and increase its number incrementally

In case your platform performance decreases or you face other technical issues while trying to add new users and handle them, it should also become an indicator to consider legacy code migration as a cost-efficient business initiative.

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Why Are Legacy IT Systems Still Used?

The biggest surprise is that lots of companies still prefer using outdated legacy systems even if proposed to modernize and update it. Why?

‘Better left alone’ is the argument of many IT system owners as their software still gets some work done. So, many entrepreneurs just don’t want to dive into the technical aspects and/or bring innovative technologies to their legacy systems that still work.

Apart from the above reasons, owners of legacy platforms still use them due to the following concerns.


Changes lead to many uncertainties and risks

Many entrepreneurs take innovations and modifications as risky initiatives and uncertainties. These stop legacy system owners from modernizing their current platforms as they still get some work done.

However, this viewpoint is cost- and time-inefficient as the risks of legacy code migration are far less than potential financial losses from a delay in deciding whether to migrate now or later. The longer system works the higher chances are to overpay for its modernization in the future.


The current legacy system was built as pricey tailor-made software

Multiple legacy systems were built as expensive custom solutions that solve specific problems of tailor-made business processes. This reason prevents lots of system owners from legacy code migration as they try to stall for time and drain dry using their platforms.

But the high initial price of a current legacy system doesn’t mean it would live and operate longer without bugs, errors, and a need to modernize it and keep working. Even though you may have spent heavy costs on your custom software, you can still save more funds on modernizing your platform now compared to the potential future costs.


Overlapping legacy issues with new frameworks

Some entrepreneurs are keeping their legacy systems alive through overlapping lots of issues with new technologies. It means there are special frameworks, libraries, and tools that allow to wrap the legacy code full of issues and provide end-users with a new interface and features.

The core disadvantage of this method is that the more frameworks are used, the more difficult it will be to modernize the legacy system. Most commonly, system owners will need to perform pricey re-engineering or even replacing activities as the number of the so-called wrappers and project complexity will surpass the chances to recover the platform and get off cheap.


If one or several of the above statements resonate with you, then we recommend you consider legacy software migration as a great opportunity to make your system performance- and cost-optimized.

Why You Shouldn’t Avoid Software Migration

Here we want to cover the key dividends you lose while avoiding software migrations for your business IT system.


Optimize software costs

One of the main triggers to migrate your outdated software to cloud is cost optimization. And many product owners and entrepreneurs consider the initial licensing fees for cloud computing as even more expensive and risky initiative than continue supporting their current outdated systems. But, in fact, they keep paying above the odds and here is why.

Even though cloud software licensing is rather pricey compared to on-premises solutions, the overall costs for making your system operate in cloud are much lower than those for on-premises software.

It becomes possible as most technical costly activities are included in the annual software licensing fee and are handled on the cloud provider’s side.

Considering the costs for on-premises systems, you can truly cut down initial licensing fees, but you are required to handle and pay for a great deal of over-priced IT staff like maintenance and updates of the hardware, network, security, databases, and many others.

This means you should consider the migration from legacy systems to cloud as a long-term perspective with vivid benefits that you will get starting on day one.


Increase performance and start integrating easily

The more years pass from the first launch of your system the more potential performance issues you may face. It’s normal as any software becomes outdated even though you perform proper and timely updates and performance audit. The reason is that old technologies and programming languages provide lower performance and have worse development support than the newest tools.

For this reason, migration from legacy systems to cloud is a time- and cost-effective initiative to revive and even boost your system’s performance which leads to a better user experience for your customers.

The fact is that cloud computing utilizes modern tech stacks and follows the best IT practices handling all updates, upgrades, releases, and performance monitoring on the provider’s side.

What’s more, your old and outdated legacy software presumably has lots of limitations and financial barriers in terms of the freedom of integrations with 3rd party tools that you need for your business. That’s also normal as most legacy code systems were integrated with a specific number of platforms and services in a tailor-made fashion and currently have no flexibility for new integrations from a technical point of view.

Here comes the migration of legacy systems to cloud that helps you forget about costly integrations and allows you to connect with the most popular and demand-specific tools, platforms, and services you may need within a couple of minutes or hours for no additional fees.


Make your product user-friendly

No user-friendly experience for legacy platforms is also normal as your outdated software built many years ago cannot compete with modern and brand-new solutions with the latest technologies and user interfaces.

This means migration from legacy systems to cloud is a great initiative to renew and redesign your system’s user interface and experience layers so that both your employees and customers will get what they really need. Why you should be interested in making your product user-friendly except for end-users’ satisfaction?

Blunting ROI. The better user-friendly interface you provide the more leads and visitors you can transform in loyal clients thus increasing the return on investments for your business.

How to Deal with Legacy Code Maintenance

While you’re considering legacy migration, it’s still a high-priority issue to know how to maintain your legacy code right now and here’s a quick checklist for your in-house team.


Comment and Document

Start with the existing documentation and code comments left by previous engineers that were working on your system. Most codebases include the file which gives the answers to key potential questions like how, when, and where a project should technically operate.

In case a development team spots this file, they should go through it and get a basic understanding of the core components and the code intend the original author wanted to express.

However, there are still some projects without a file that complicates the initial code audit process and maintenance. In this case, your developers should perform a legacy code analysis and suggest whether it’s worth investing your time and funds into refactoring, or it makes more sense to rewrite the code from scratch.


Test Everything

Testing and quality assurance are the core activities that allow you to keep working with legacy code in an error- and bug-free way.

Through manual and unit tests, technical specialists can maintain your existing legacy code software and minimize the ratio of errors and even enable the development team to build new features without full refactoring.


Refactor But Not Rewrite

These initiatives are potential problem solvers which will help you improve the system’s health gradually. Put it simple, code refactoring means that developers perform a legacy code analysis, update, and optimize code the way it works correctly, but not reengineering legacy systems and their codebase from scratch as it’s a time- and cost-consuming activity.

If you get feedback from your development team that it’s hardly possible to revive the existing legacy code through refactoring, then we recommend considering legacy migration as the most cost-compressed initiative for your business.

Migration From Legacy System to Cloud

Before you start the legacy migration process, you need to choose the modernization method. It’s of high importance for your business as it will influence the complexity, time, and funds you will need to spend on legacy code migration.

Specifically, there are only two strategies:


  • Evolutionary

Put it simple, the evolutionary method means that developers replace old components with new ones and your system avoids shutdowns. This strategy is far less painful than the revolutionary method as it doesn’t prevent your business processes and allows your system to operate.

What’s more, evolutionary modernization can be done side-by-side and prolonged in the future.


  • Revolutionary

It’s an antipole to the evolutionary method as it implies a full system rewriting and substitution with building a new codebase from scratch. For sure, it cannot be done without a temporary system shutdown and is a great choice if you have an old and monolithic IT system without the possibility to modify it.

Most commonly, entrepreneurs and product owners embrace the revolutionary legacy migration when it’s the only possibility to revive their platforms as this method provides significant risks to business operation.


Once you decide on the legacy modernization strategy, we also recommend choosing the right approach of working with legacy code which will be followed by the development team.

The legacy system migration approach refers to a modernization model which is based on the number of changes and the overall project complexity.



This approach is among the quickest and most cost-compressed options. In short, it means taking the existing components of your IT system, encapsulating its data, and transforming it into an accessible API for the future reuse.

Encapsulation refers to introducing a brand-new interface of the current legacy platform without solving potential maintenance challenges.

So, choose this approach of working with legacy code if you have a well-written and fully functioning system that is required to update and provide end-users with an upgraded user interface remaining the core business logic.



This approach is also among the most time-, cost- and risk-optimized and refers to a redeployment of your current IT system to another cloud, virtual, or physical infrastructure. It implies no business logic, codebase, and functionality modifications are required.

It becomes the case for your business when you want to improve the hosting performance, boost reliability, security, and get more freedom of releasing new updates.

It’s worth mentioning that rehosting is one of the possible options for migrating your IT system to cloud among replatforming and refactoring.



The replatforming approach means migrating your legacy code software and/or its key components to a new platform with hardly any code modifications. So, your core code structure, features, and architecture will remain the same.

Choose replatforming in case you have concerns that your end-users won’t adjust and like the new system.

Among the core benefits of this approach are cost optimization, basic cloud features and advantages, and low efforts.



This means optimizing and slightly adjusting your existing legacy code and its structure without moderate changes to the business logic and scenarios.

Refactoring includes modifying backend components to perform seamless legacy code migration to cloud computing. This approach provides you with basic cloud features and the microservices infrastructure.

Choose refactoring when you want to decrease the technical debt, increase flexibility, and boost performance.



This approach refers to designing a new architecture and significant code structure changes. Being a more advanced and complex technique, rearchitecting can potentially provide more risks.

Choose the method of reengineering legacy systems when you want to modify and improve the existing product functionality utilizing a new tech stack for easier support and maintenance in the future.



This method implies rewriting your legacy code software from scratch making it a brand-new, completely updated, cloud-based solution. Rebuilding includes multiple technical activities including DevOps for legacy systems, introducing new technologies like containers, microservices, etc.

Choose this approach of data reengineering and migration when you want to redesign the legacy from scratch and get a flexible IT system with high performance and reduced maintenance costs.



Replacing means retiring your existing legacy code software and replacing it with a brand-new, tailor-made, cloud-based solution. This method is worth considering in case none of the above approaches fits your situation and there is no point to save the current system.

Choose the legacy system replacement strategy of working with legacy code if you want to fully change your legacy platform with a new one from scratch and when you are ready for a large scope of planning, development, and deployment activities. This option is a landslide winner if your current business needs fully correspond with building a new system.


Legacy Code Migration Approaches By Complexity and Efforts

Legacy Code Migration Approaches By Complexity and Efforts

How We Got 200X Performance Boost with System Migration

At Ascendix, we’ve helped multiple companies migrate legacy systems to cloud, and here is one of our success cases.



We have been supporting and improving a large KnockoutJS-based application running on the .NET 4.5 server and we decided to migrate the app from .NET to .NET Core.


Migration Challenges & Objectives

  • Separate the backend and front-end logic to get rid of old code parts and low codebase quality
  • Boost the development time and accelerate the page loading speed
  • Avoid updating third-party libraries that would have greatly saved much time in the long run
  • Run the application on Linux and leverage multiple benefits from using Docker and Kubernetes
  • Start using Visual Studio Code for development.


Main Roadblocks

Lack of several libraries supported by .NET Core However, we found that there were no analogs to XML which forced us to act radically and remove the XML-related functionality.


Key Results

  • Boosted the application performance by 200 times
  • Reduced environmental and infrastructure costs
  • Saved up to $428/mo
  • Switched to F2 nodes on production which allowed us to save additional $446/mo.


We have just described a particular case of reengineering legacy systems and shared our results achieved, but each situation is unique, and the results will be different. If you need help with legacy system migration, just drop us a line and we will get back to you with a ball-park project estimate.

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Software Migration with Ascendix

Having a 10-year expertise in reengineering legacy systems and software migration, your challenge becomes our solution. Our certified technical teams will propose the most cost- and time-efficient solution during the discovery session for your project based on your business needs and technical requirements.

We utilize the latest tech stack to migrate legacy systems to cloud and keep them sustained, secure, and high-performing so that you can focus on the core business processes and forget about technical issues for years.

You can choose from a variety of flexible engagement models that will suit your budget expectations and preferences in the best way possible.

In case you want to cut down costs and leverage high-skilled talents, we can offer our offshore technical teams from Europe.

Want to fully manage our technical specialists and extend your in-house team? That’s a deal as we have a dedicated team model. Otherwise, fully delegate all legacy software migration activities to us so that we handle the legacy system migration from A to Z.

Ultimately, you can blend our talents so that you collaborate with US-based business analysts and project managers while our European technical teams transform your system.


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