Software modernisation involves updating or transforming existing systems to align with current technologies, architectures, and evolving business needs. This often includes cloud migration, rearchitecting for scalability and flexibility, or replatforming to modern environments.

As businesses depend more on digital infrastructure, outdated systems can become a liability, slowing operations, increasing maintenance costs, and exposing organisations to security risks. A software modernisation process reduces technical debt, enhances system performance, and streamlines development and deployment. It also strengthens security by replacing unsupported components and enables businesses to adapt rapidly to market changes.

Ultimately, a legacy software systems modernisation process is a critical driver of innovation, risk reduction, and maintaining a competitive edge.

How do I know if my software needs modernisation?

Identifying the need for a software modernisation project is essential to prevent inefficiencies and escalating risks.

Key signs you should pay attention to include:

• Frequent downtime or system crashes disrupting operations.
• Slow system performance that frustrates users and hampers productivity.
• High maintenance costs consuming a large portion of IT budgets.
• Outdated technology stacks that limit functionality and complicate hiring skilled developers.
• Lack of scalability preventing the system from handling increased workloads.
• Difficulty integrating with newer tools, platforms, or APIs.

These issues indicate that your existing legacy systems may no longer meet business golas and needs and could greatly benefit from a modernisation process.

Stay competitive and ensure long-term business success by modernising your applications. With our approach, you can start seeing real value even within the first 4 weeks.

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What are the common approaches to software modernisation?

There are several established software modernisation strategies, each with distinct complexity, cost, and impact. Choosing the right approach depends on your goals, technical constraints, and the current system state.

Let’s look at them in more detail:

Rehosting (Lift and Shift)

Rehosting means moving applications to new infrastructure, often cloud-based, without changing the core architecture. This is typically the fastest and least disruptive method.

Replatforming

Replatforming means making slight modifications to optimise applications for new platforms, improving performance and scalability with minimal existing code changes.

Refactoring

Refactoring means restructuring legacy code to improve its structure and performance while maintaining its behaviour. This approach is often used to make applications more maintainable and compatible with modern environments.

Rearchitecting

Rearchitecting means redesigning the application’s architecture to support better scalability, flexibility, or new business requirements. This often involves moving from monolithic legacy systems to microservices or serverless architectures.

Rebuilding

Rebuilding means rewriting the application from scratch using modern tools and frameworks. Though resource-intensive, it allows for maximum customisation and alignment with current business processes and needs.

Replacing

Replacing means retiring outdated legacy systems entirely and adopting a new solution, often a commercial off-the-shelf (COTS) product or SaaS alternative. This is ideal when the legacy system no longer supports business processes effectively.

Often, organisations combine these strategies depending on system complexity and priorities.

What are the benefits of modernising existing systems?

A legacy systems modernisation delivers numerous benefits that boost business agility and efficiency. The most significant ones include:

• Improved scalability and better business processes – modern architectures enable easier scaling to meet workload demands.
• Faster development cycles – agile and DevOps practices accelerate feature delivery and responsiveness.
• Lower operational costs – reduced need for workarounds and specialised legacy skills cuts maintenance expenses.
• Enhanced customer experience – faster, more reliable software systems improve customer satisfaction and retention.
• Stronger security and compliance – updated security standards reduce security vulnerabilities and ease regulatory adherence.
• Access to cloud-native systems -cloud tools like AI, automation, and analytics open new innovation opportunities.

What are the biggest challenges in software modernisation?

While transforming legacy systems offers significant benefits, it also presents several challenges that organisations must carefully manage.

Key obstacles – and ways to mitigate them – include:

System complexity

Undocumented logic and interdependencies make legacy systems hard to modernise. To mitigate it, conduct thorough audits and use automated tools to map dependencies.

Data migration risks

Data loss or corruption can occur during transfer. To mitigate it, implement staged migrations, rigorous validation, and backups.

Downtime risks

Service disruptions may impact users. To mitigate it, use phased rollouts, blue-green deployments, or parallel runs to minimise downtime.

Stakeholder resistance

Change may be met with pushback. To mitigate it, engage users early, offer training, and communicate benefits clearly.

Integration issues

New systems may not easily connect with legacy components. To mitigate it, use APIs, middleware, or hybrid architectures to ensure interoperability.

Unclear business goals

Without clear objectives, modernisation can misalign with needs. To mitigate it, define goals clearly and involve leadership in strategy alignment.

What technologies are used in legacy software modernisation?

Legacy software modernisation leverages a range of modern technologies to enhance scalability, maintainability, and performance. These technologies form the backbone of contemporary software architecture and delivery.

Key tools and platforms include:

• Microservices Architecture – breaks down monolithic applications into smaller, independent services that can be developed, deployed, and scaled separately, improving agility and fault tolerance.
• Containers (e.g., Docker) – encapsulate applications and their dependencies into lightweight, portable units, simplifying deployment across different environments and streamlining development workflows.
• Kubernetes – an orchestration platform for managing containerised applications at scale, enabling automated deployment, scaling, and maintenance of containers.
• Cloud Platforms (AWS, Azure, Google Cloud Platform) – provide flexible, scalable infrastructure and a wide array of services that support modernisation efforts, such as compute, storage, databases, AI tools, and more.
• APIs (Application Programming Interfaces) – facilitate communication between legacy systems and modern systems, enabling integration and data exchange without full-scale replacement of older components.
• Serverless Computing (e.g., AWS Lambda, Azure Functions) – allows developers to run code in response to events without managing servers, reducing operational overhead and improving scalability.
• CI/CD Pipelines (Continuous Integration/Continuous Deployment) – automate code testing, integration, and deployment, accelerating development cycles and ensuring more reliable software delivery.
• Modern Data Platforms (e.g., Snowflake, BigQuery, Apache Kafka) – enable real-time data processing, analytics, and storage at scale, replacing outdated databases and improving decision-making capabilities.

Thanks to our work, we decreased the lead time for changes from 2 months to 1 day, improved change failure rate from over 30% to below 10%, and saved 50% of the client’s Cloud costs.

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How do we measure the success of a modernisation effort?

Success of a legacy system modernisation is measured through a combination of technical and business metrics, comparing performance before and after the process:

• System uptime – improved availability signals enhanced reliability.
• Performance gains – faster response times and better load handling reflect system improvements.
• Reduction in support tickets – fewer issues indicate greater stability.
• Cost savings – lower infrastructure and maintenance costs demonstrate financial benefits.
• Deployment frequency – more frequent releases show increased agility.
• Lead time for changes – reduced time from code commit to production points to efficient pipelines.
• User satisfaction – positive feedback and higher engagement indicate better user experience.

A great example of a successful implementation of a software modernisation strategy is a large-scale transformation discussed with James Holmes, an Interim Programme Director and CIO leading the initiative, in our IT Insights InsurTalk series. The project was delivered with zero critical defects at go-live, unlocking great improvements in data integration, overall efficiency, and customer service.

Watch the full video interview with James Holmes:

FAQ

How long does a typical legacy modernisation project take?

The duration of a modernisation project varies widely depending on the size, complexity, and the current state of the system. Smaller or less complex applications might be modernised in just a few weeks, while larger, mission-critical existing systems can take several months to over a year. Many organisations adopt an incremental approach, breaking the project into manageable phases to reduce risk and deliver value continuously throughout the process.

Can I modernise just part of my legacy applications?

Absolutely. Incremental software systems modernisation allows you to update specific components or modules without rewriting the entire system at once. Techniques like the Strangler Fig Pattern enable gradual replacement, where new functionalities are built alongside the legacy system and slowly take over, minimising disruption and spreading investment over time.

How do I choose the right application modernisation strategy?

Selecting the best modernisation strategy depends on multiple factors including your business objectives, the complexity and architecture of your current system, the level of technical debt, available skills within your team, and your desired timeline for results. A thorough assessment by experienced professionals can help evaluate these factors and recommend an approach that balances risk, cost, and impact effectively.

How does legacy application modernisation help reduce technical debt?

Technical debt accumulates when shortcuts, outdated code, or legacy architectures hinder system maintainability and scalability. Outdated systems modernisation addresses this by refactoring, rewriting, or replacing legacy systems and components, thereby reducing complexity and improving code quality. This cleanup enables more sustainable development practices and supports future growth with fewer obstacles.

Can legacy systems modernisation help with software integration?

Yes, one of the significant benefits of legacy code modernisation is improved integration capabilities. Modern architectures often leverage APIs, event-driven systems, and modular designs that facilitate seamless communication between disparate systems. This flexibility makes it easier to connect with third-party services, adopt new tools, and extend functionality without extensive rewrites or disruptions.

Assure seamless migration to cloud environments, improve performance, and handle increasing demands efficiently.

Modernisation of legacy systems refer to the process of upgrading or replacing outdated legacy systems to align with contemporary business requirements and technological advances.

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Future Processing – case study

In the beginning – 3,5 years ago – my development team at Future Processing was just a small bunch of 3 people, that gradually expanded to 9. Then, within a span of only 8 months, we grew to 25 team members, including two leaders as one definitely wasn’t enough. This was quite a challenge, especially since every time there was a new addition to the team, we all had to go through every stage of the team-building and development process again. What a ride! At our peak, there were nearly 40 people, each with different areas of expertise and years of experience.

Now, we have all our professional positions covered, from developers and designers to product owners and project managers. We can easily scale up and down, according to project needs and requirements. Team members with years of experience and vast knowledge cooperate with newbies who are just learning, also taking care of their onboarding process, according to their areas of specialisation. Everyone knows who’s responsible for what, and it’s been like this for a while now.

But how was it at the very beginning? And what are the real challenges facing those who are thinking about building a development team? Let’s have a look.

Challenges to be faced

The problems generally pertain to three different but intersecting areas: people, management and the work environment.

People

• Hard and soft skills
  You need to find people who are not only specialists in specific areas but who also have some universal social skills, to ensure smooth cooperation.
• Roles and responsibilities
  A clear allocation of responsibilities and labour that is meaningful and comprehensible to every team member is super important, yet harder to achieve than may be expected.
• Teamwork and engagement
  It can also be a challenge to get the team to work together and towards mutual success while maintaining good levels of engagement and motivation

Future Processing – case study

For us, the “people” challenge was the most difficult, as we needed to hire a number of professionals specialised in quite a narrow field of IT, i.e. the node.JS framework. The supply of people with this type of expertise profile is pretty low, especially since we also wanted them to have good communication skills, which made our mission even more difficult. How did we deal with this situation? We decided to hire people who — in our opinion — would be the best fit for the team (even if they meet only one of our requirements), and then we spent a lot of time training them and working on their weak points.

Management

• Leadership
  Management styles and selected methodologies can be decisive factors in the team-building process as poor leadership may hold a team back, create confusion, and bring the entire project to failure.
• Communication
  Good communication largely depends on the leaders – their openness, honesty and ability to work with different characters and get them to work well with one another.
• Conflicts
  The more people you have on your team, the more potential conflicts may emerge along the way. Handling them is one of the hardest management tasks.
• Evaluation
  Employee evaluation is also challenging, as every piece of criticism should be constructive, while all weaknesses and vulnerabilities have to be addressed in order to be mitigated.

Future Processing – case study

Our team is made up of many individuals of strong character, which can be difficult to manage; we all had to learn how to cooperate with one another. Even today, whenever a new person joins the team, we need to find just the right place for them in our small ecosystem, in order to ensure flawless collaboration. Sometimes things can get pretty tense between teammates, and sometimes everything runs smoothly, but there’s always something to work on and improve.

Work environment

• Infrastructure
  There are also some technical details that need to be taken care of whenever you build a team, such as preparing proper workspaces and providing professional tools for collaboration and communication, or giving access to crucial data.
• Training
  Your focus on constant learning and improvement is absolutely necessary and should be reflected in, for example, employee training sessions or participation in industry conferences or hackathons.
• Atmosphere
  The team-building process is only effective in an atmosphere of openness and support among everyone, regardless of their place in the hierarchy.

Now that you are familiar with the most common challenges that often occur when building a development team, it’s time to show you how to overcome them and make your project a success.

Building a development team: a step-by-step guide

Bruce Tuckman identified the 5 main stages of the team-building process: forming, storming, norming, performing and adjourning. However, I will focus on the first three phases only, as they are the most important in the very beginning.

5 steps of the forming stage

1. Define your needs: team size, goals, detailed project requirements.
2. Establish your values and principles of cooperation.
3. Create a proper work environment.
4. Select the right specialists, e.g. juniors + seniors + leader (project manager/scrum master).
5. Introduce your chosen management methodology.

Future Processing – case study

As I mentioned earlier, our team grew significantly in a span of just 8 months, and every time a newcomer joined us, we repeated all of the team-building stages over and over again. But once our team became more or less fixed, we ran a workshop to lay down the main principles of teamwork. We developed a written contract containing a set of rules for the cooperation, communication and knowledge transfer processes. Every team member had to sign it, and every newbie has to do the same today.

5 steps of the storming stage

1. Have leaders get to know their team members better: their individual skills, differences and personalities.
2. Assign tasks in accordance to individual predispositions.
3. Identify obstacles and find ways to overcome them.
4. Address potential conflicts between team members and deal with them constructively.
5. Be flexible and ready to adjust.

Future Processing – case study

When people started feeling more confident in their roles, the division of responsibilities according to individual predispositions and skills presented itself naturally. We focused more on handling problems that, previously, did not seem to have any clear cut solutions. Minor conflicts were resolved between team members, and only major ones required consultation with team leaders.

5 steps of the norming stage

1. Establish some sort of consensus.
2. Work within certain procedures in order to let everyone know what to expect.
3. Focus on cooperation and collaboration, following the rules of your selected management methodology.
4. Strive to improve overall performance.
5. Track your progress.

Future Processing – case study

The transition to this phase was so smooth and natural, that it was virtually unnoticeable. Now, we follow clear and simple rules — rules that everyone knows, comprehends and respects. As leaders, we collect as much data as possible to track our progress and improve our work. Our communication skills are also on an excellent level – both among team members, and between us and our client. We are also proud of our flawless and efficient onboarding process, where every new team member receives a massive amount of support and is able to quickly learn how we work.

Of course, while going through all of these stages, there are some other things you shouldn’t forget about, as they can make your cooperation more pleasant, less stressful, and also much more enjoyable — such as:

• organising team-building activities,
• celebrating small wins,
• always encouraging open communication that builds trust.

Benefits of using this approach

One of the main benefits of using this approach is being able to establish a well-functioning development team – in a relatively short amount of time and while working as a whole. This also includes:

• increased work efficiency,
• greater employee satisfaction and motivation,
• less frustration,
• higher likelihood of project success.

There is also one more thing that sounds promising for the entire company: a well-organised development team is far more likely to carry out many more successful projects, together.