LEGACY SOFTWARE MODERNIZATION

We rebuild outdated systems so you can move fast, stay secure, and build the future of your business.

Let’s talk

Trusted by great companies

ATT
RoyalCaribbean logo white
Asseco
Microsoft logo white
Contentsquare
Asset 1sofa 11

WHAT’S HOLDING YOU BACK

Old systems drag everything down. You’re dealing with:

  • High maintenance costs and rising risks
  • Slow performance and sluggish UX
  • Gaps in compliance and security
  • Problems scaling or integrating with modern tools
  • A backlog of technical debt
  • Fear of breaking business continuity mid-transition

THE PROCESS — 5 steps, clean code, and minimal disruption

01

Discovery


We dig into your current system. That means reviewing your codebase, architecture, third-party integrations, and documentation (if it exists). If it doesn’t, we reverse-engineer your logic and behavior.

While the tech is important so is your business strategy. We make sure to understand the goals you want to accomplish with a modernized system.

We also talk with your team to map out how the app works in real life, not just how it’s supposed to work.

You’ll get:

  • A full system audit
  • Pain points and quick wins
  • A high-level risk assessment
  • Realistic modernization options

02

Planning

We define a modernization roadmap that fits your business. You might need a full rebuild. Or maybe we can refactor key modules and gradually phase out the old parts.

We balance speed with safety, always protecting your current operations.

You’ll get:

  • A tailored strategy (refactor, rearchitect, rebuild, etc.)
  • Timeline and team breakdown
  • Cost and scope estimate
  • Migration or transformation plan

03

DEVELOPMENT

Here’s where our team gets to work. We break the system into manageable components and modernize them one at a time.

We update outdated code, replace deprecated dependencies, improve the UX, and rewrite services for better performance. CI/CD pipelines keep everything moving fast and safely.

You’ll get:

  • Clean, modern code
  • Scalable architecture (e.g., microservices if needed)
  • Updated UX/UI
  • Full QA coverage at every step

04

DEPLOYMENT

We release in phases, starting with staging environments and test data. You’ll sign off before anything goes live. When we deploy, we monitor performance closely and keep your team in the loop.

You’ll get:

  • Risk-free rollout
  • Minimal or no downtime
  • QA signoff and release notes
  • Real-time monitoring and feedback loop

05

SUPPORT

Modernization isn’t a one-off event. We stick around to fix bugs, make small updates, and help your team own the new stack. If needed, we’ll train your developers and document everything thoroughly.

You’ll get:

  • Post-launch support and maintenance
  • Documentation and training
  • Roadmap for future updates
  • A real partner, not just a vendor

The outcome? More productivity, reduced costs and staying ahead of your competition.

Great, but why DECODE?

Here’s why we’re the right company to modernize your legacy systems:


Experience with complex domains

We’ve modernized software in industries where getting it right isn’t optional, like healthcare, fintech, telecoms, and rail. We’re used to working with strict compliance, high-performance requirements, and large codebases.

Secure by design

We build with security in mind from day one. That includes secure coding practices, access control, audit trails, and compliance with standards like HIPAA, GDPR, and SOC 2, depending on your needs.

Technical depth

Our engineers have experience with legacy systems built in Java, .NET, and even Delphi. We also work with modern stacks like Kotlin, Swift, React, and cloud-native services on AWS, GCP, and Azure.

IoT expertise

Your systems might be tied to machinery, making you even more reluctant to make changes. We have experience in creating software that seamlessly communicates with any device, so you can rest assured the modernization will not disrupt your business.

Let’s talk

50208966073 4b02d29710 k 1

But don’t take our word for it

Here’s what our clients have to say about us.

What struck us the most with DECODE is the versatility of their engineers who were able to tackle every problem and respond to every challenge with diligence and persistence. Their UI/UX designer showed extraordinary creativity and was a source of excellent ideas. They were an excellent bunch to work with!
William Skannerup
Founder at Gentoo App & VeridenKey
DECODE made an excellent job working with us on one of our most strategic projects with one of the biggest, most global clients within the industry. With great energy, great technical knowledge, very quick understanding of the situation and what was needed to be done, including the willingness to walk the extra mile, they were a big part of make this project so successful. True professionals and very good output with high quality and speed!
Christoffer Möller
COO at Snowfall
DECODE are one of our most trusted suppliers and we’re pleased to have them as a partner.
Alastair Mitchell
Senior Vice President Engineering at Metaswitch Networks →
DECODE’s in-depth knowledge of creating real-time communication apps was exactly what we needed for such a demanding mobile app solution. Because of their high quality and speed, I consider them as a five-star agency.
Jack Templin
CEO at Thoughtcap
They brought in the expertise in the area of mobile application architecture, automated deployment & testing, introducing new development paradigms and workflows.
Karen Sallick
I am continually impressed by the level of pride and ownership that DECODE takes in the work they perform for us. They treat our products as if they are their own, which translates into better user experiences for our customers.
Kenneth Huebsch
Software Engineering Manager at Qrypt →

Still not convinced?

Here are verified Clutch testimonials from our satisfied clients.

This could be the start of a great partnership

Fill in the short form below, or skip to the bottom to arrange a chat directly with our Strategic Partnerships Manager. Either way, we’ll be back in touch as soon as we can to arrange an informal call.

Don’t worry, any information you give us will only be stored for business purposes. Find out more in our Privacy Policy.


or
Damir Plejic

Arrange a chat with Damir, our Strategic Partnerships Manager.