Application modernization without stopping the business.
The application that runs your orders, your stock or your billing was written years ago, on a server and a framework nobody supports anymore. We modernize it in waves. Each wave is tested against the old system on real data, and the old one keeps working until your team has approved the switch.
Nightly parallel run
Wave 3, order management
Yesterday’s orders went through the old application and the new one. Compare every result before the team switches wave 3 on Thursday.
- 06:30:02Compared 1,412 orders. Totals, taxes, discounts and delivery dates, line by line.
- 06:30:05Found 3 differences. All three on orders with a partial delivery.
- 06:30:07Traced 2 to the old code. A rounding rule written nowhere but in a 2011 function.
- 06:30:09Traced 1 to the new code. A customer discount missing from the migrated data.
- 06:30:11Drafted the fix and a test so the rule and the discount are checked on every release.
Wave 3 switch: waiting for your team. Nothing moves to the new application until an engineer and the order desk have checked the three cases.
Where your legacy software could go next.
The first two are real projects. Client names stay private; the facts are the ones published at delivery. The last two are the situations we are most often called for.
Real project: an international distribution group, more than ten applications
BeforeThe group’s management applications ran on a mixed PHP and .NET base, with MariaDB, MongoDB and SQL Server, on operating systems and middleware partly out of support, and servers that did not match from one instance to the next.
AfterWorking inside the group IT department’s project team, more than ten applications were modernized in waves, one application at a time, on supported systems and one unified cloud hosting, under one constraint: operations could not stop.
Real project: a B2B lead generation company that kept its stack
BeforeThe product team had stopped delivering, and management no longer knew what to ask of its developers.
AfterThe JavaScript stack was kept as it was, with no technical rebuild. The frame around it was reset: an internal product owner was recruited and trained, and the team delivered again with no dependency left on us.
The tool only one retired developer understood
BeforeA critical application, no documentation, and business rules nobody can state until something breaks.
AfterThe rules are read out of the old code, written down and turned into tests before a single screen is rebuilt.
The desktop software that must go to the web
BeforeAn application installed on each computer, a shared database on a local server, and no access from outside the office.
AfterA web application with the same data and the same habits, reachable from anywhere under proper access rights.
What are application modernization services?
Application modernization services take business software that still does its job but has become risky or expensive to change, and bring it onto supported technology. Depending on the case, the application is moved to new hosting, partly rewritten or rebuilt, usually in stages. The goal is software your team can change again, without losing the rules the old one carried.
Legacy application modernization rarely fails on technology. It fails when the old system’s hidden knowledge gets lost on the way: the rounding rule, the exception for one large customer, the batch that runs on the last day of the month. That is why we read the old code before we plan anything, and why each migrated rule becomes an automated test.
Nor does every legacy system need a rewrite. Some only need a new server, an upgraded runtime and a cleaned-up database. Others hide a process problem that no new code will solve. The first job is to tell which case you are in, which is what a code audit does.
Rehost, refactor, rebuild or replace: which modernization fits your application?
Six options, from the lightest to the most radical. Most portfolios use several of them, one per application.
| Criterion | What changes | When it fits | What to watch |
|---|---|---|---|
| Keep and secure | Security patches and monitoring, nothing else | Stable software, due to be replaced within a few years | The risk grows every year it stays |
| Rehost | New hosting, same code | The server or data center is the problem | Old code stays old |
| Replatform | Supported runtime, database and operating system | The code is sound, the foundations are out of support | Hidden incompatibilities, found only by testing |
| Refactor | The code is reorganized and cleaned up, piece by piece | The software is right, but every change is slow and risky | Needs tests before it starts |
| Rebuild | New software, same business rules | The technology is dead or the design blocks the business | Rules lost on the way, if not written down first |
| Replace with a package | A market product instead of custom software | The process is standard and nothing sets you apart | You adapt your process to the product |
Your business keeps running while the software changes.
Security and dataThe old system stays on until the new one has proven itself.
Each wave runs side by side with the old application on real data, and your team decides when to switch.
The hidden rules are written down first.
What the old code does is documented and turned into tests before anything is rebuilt.
Data migrated with checks and a way back.
Every migration is rehearsed, counted and reconciled, with a rollback plan written before the switch.
The result is yours.
Source code, documentation and deployment scripts are handed over, on mainstream technology another team can take over.
Hosting where you decide.
Your servers, a private cloud or a European cloud, chosen for the data each application holds.
How your modernization runs, wave by wave.
First
Audit what you have
We read the code, the data and the servers, and talk with the people who use and maintain the software. You get the state of each application and the option that fits it.
Then
Plan the waves
Applications are grouped into waves, ordered by risk and value. Each wave has a written scope and a fixed price before it starts.
Each wave
Migrate and run side by side
The new version runs next to the old one on real data. Differences are traced and fixed until your team approves the switch.
At the end
Switch off and hand over
The old system is archived with its data. You keep the documentation, and choose who maintains what comes next.
What the cost of an application modernization depends on.
Between moving a sound application to new hosting and rebuilding a twenty-year-old system, the audit places each of your applications on the scale, and each wave is priced in writing before it starts.
Read the custom software cost guide, with market ranges- 01The number of applications, and how tangled they are with each other.
- 02The size and state of the code, and whether tests exist.
- 03The volume and quality of the data to migrate.
- 04The systems each application exchanges data with.
- 05How long the old and new systems must run side by side.
- 06The target hosting, and the security rules of your sector.
Application modernization: the questions buyers ask us
How long does an application modernization take?
It depends on the number of applications and their state, which is why we audit first. A portfolio is modernized in waves, and each wave gets its own scope and fixed price before it starts, so you never commit to a multi-year project in one go.
Should we rewrite the application or refactor it?
Rewrite when the technology is dead or the design blocks the business. Refactor when the software does the right things but every change is slow. Many applications need neither: a supported runtime and new hosting are enough. The audit tells you which case applies, application by application.
Can the old system keep running during the migration?
Yes, and that is how we work. The old and new versions run side by side on real data during each wave. Your team switches only once the results match, and the old system stays available until the switch is confirmed.
We have no documentation and the original developers are gone. Is that a problem?
It is the usual situation. The rules are read out of the code and the data, then checked with the people who use the software every day. What we find is written down and becomes a test, so the knowledge stays with you this time.
Can you move our applications to the cloud, or keep them on our servers?
Both. We can move applications to a European cloud, a private cloud or your own servers, and bring operating systems, runtimes and databases up to supported versions on the way. The choice depends on the data each application holds.
Can AI be added to the modernized software?
Yes, where it removes real work: reading incoming documents, drafting entries, answering questions from your own data. A modernized application with a clean data model is a much safer place for AI than the old one, and we plan for it from the first wave.
Related services and guides
- Custom software development When the software has to be built from scratch.
- Code audit The first step: know the state of what you have.
- Application maintenance To keep the modernized software up to date.
- Business applications When the old tool becomes a new internal app.
- AI integration To add AI to the software once it is modernized.
- Custom software cost guide Market price ranges, with their sources.
- Technical debt, explained Where it comes from, what it costs, how to pay it down.
Make yesterday’s software an asset again.
Tell us which application worries you and what it runs today. We reply within one business day to set up your free 30-minute assessment, with a first view of the option that fits it.