Legacy application modernisation
Legacy System Modernisation
The system still runs the business. It also runs on software that stopped getting security patches years ago, and only one person knows how it works.
One of our CTOs reviews the system, plans the rebuild and leads it. A small team of AI-driven developers rebuilds it on a modern stack, one piece at a time, at a fixed price per phase.
Signs Your Legacy System Is Now a Risk
One person knows how it works
The system was built by a contractor in 2009 or a staff member who has since left. Every change waits for the one person who still understands it, and they want to retire.
The platform is out of support
Access, VB6, classic ASP, old .NET Framework, PHP 5 or AngularJS. Security patches have stopped, and your cyber insurer and Essential Eight assessment both ask about it.
It does not connect to anything
Staff re-key data between the old system, Xero and the CRM. There is no API, so every new tool needs another spreadsheet in the middle.
Previous quotes were eye-watering
A vendor quoted a multi-year replacement programme, or tried to sell you an ERP that does ten times what you need. So the old system stays, and the risk grows.
Our Modernisation Approach
No multi-year programme and no big-bang cutover. You see working software within weeks, and you can stop after any phase.
Modernisation Assessment
We map what the system actually does, who depends on it and what data it holds. Then we cost the real options side by side: retire, replace with SaaS, refactor or rebuild.
Decision and fixed price
You get a recommendation with the trade-offs in plain language, and a fixed price for each phase. If off-the-shelf software is the better answer, we will say so.
Rebuild in slices
We replace the system one module at a time while the old one keeps running. Each slice ships, gets used and is signed off before the next one starts.
Rehearsed data migration
Data moves across in rehearsed dress runs with reconciliation reports, so go-live day is a non-event. Then we hand over the code, the documentation and the support plan.
Why Now Is a Good Time to Rebuild
to a costed recommendation you can take to the board
for every phase, agreed before the phase starts
Legacy Modernisation Pricing
Every price is fixed before the work starts. The assessment tells you the exact phase prices for your system.
Modernisation Assessment
One of our CTOs maps the system, documents its business rules and costs every option, including buying SaaS. You get a recommendation and a fixed price per phase.
Rebuild Phase
Your CTO plans and leads each phase. A small team of AI-driven developers builds one module at a time while the old system keeps running.
Typical Total
Most mid-market systems need two to four phases. You approve each phase separately and can stop after any of them.
Want the detail behind these numbers? Read our legacy modernisation cost guide.
Legacy Systems We Modernise
The target stack depends on your team and your other systems. These are the most common journeys.
| From | To |
|---|---|
| Microsoft Access and Excel VBA | Web app on PostgreSQL or Azure SQL with proper user access and audit trails |
| VB6 and Delphi desktop apps | Browser-based TypeScript or .NET application with an API for other systems |
| .NET Framework 4.x and WebForms | Current .NET on Linux containers or Azure App Service |
| Classic ASP and PHP 5 or 7 | Next.js or Laravel on a supported runtime, with tests and CI/CD |
| AngularJS and jQuery front ends | React or Next.js front end on the existing or a new API |
| Lotus Notes, FileMaker and old custom CRMs | SaaS where it fits, or a lean custom build where it does not |
How We Modernise Legacy Systems
Rebuilding old software used to be slow and expensive because most of the cost went on working out what the old code did. AI-assisted engineering has changed that. Reading old code, writing tests that pin down its behaviour and drafting documentation now take a fraction of the time. That money goes on getting the new system right.
Understand before you touch
We read the old code and watch the people who use it. Then we write down every business rule it enforces, including the ones nobody remembers. AI tools speed this up a lot, but one of our CTOs checks every rule against real usage. This is the step that stops a rebuild from losing the quirks your business depends on.
Replace in slices
We use a strangler approach. The new system takes over one function at a time, behind the same front door, while the old one keeps running. There is no big-bang weekend cutover and no 18-month wait before anything ships. If priorities change halfway, you still have working software.
Leave it maintainable
The new system runs on a mainstream stack that any competent developer can pick up, with automated tests, a deployment pipeline and documentation. You own the code. We would rather you never need us again than have you locked into a proprietary platform.
What You Walk Away With
Every phase ends with something that works, plus the paperwork your auditors and your next developer will want.
Modernisation assessment and options paper
What the system does, who relies on it, the risks of leaving it alone, and costed options including the ones that do not involve us.
Business rules catalogue
Every rule the old system enforces, written in plain English and checked against real data. Useful even if you decide to buy SaaS instead.
The new application
Built on a supported stack with role-based access, audit logging, an API, automated tests and hosting set up to your security standards.
Migrated and reconciled data
Your historical data moved across with reconciliation reports that show every record arrived intact.
Handover and support plan
Architecture documentation, runbooks, training for key users and a support arrangement that suits your team, whether in-house, with us or with another provider.
The fixed price for each phase is agreed before it starts. If the assessment shows the system is not worth rebuilding, you keep the assessment and we part as friends.
Is Legacy Modernisation Right for You?
This service suits organisations with a system that still does an important job but has become a risk to run.
A good fit if
- ✓A core business system is on an unsupported platform such as Access, VB6, classic ASP or old .NET Framework.
- ✓You have 20 to 500 staff and the system is too specific to your business for off-the-shelf software to fit cleanly.
- ✓You need the new system to connect to Xero, a CRM, a data platform or AI tools, and the old one cannot.
- ✓You want an independent view on whether to rebuild, replace or leave it, from someone who does not sell a platform.
Probably not the right time if
- ·You need a core banking or mainframe replacement programme. That needs a large systems integrator.
- ·A mainstream SaaS product already covers 90% of what you need. Buy it, and we can help you choose and migrate.
- ·You want the cheapest possible offshore rebuild with no senior oversight.
If you are not sure, start with the two-week assessment. It pays for itself in the bad options it rules out.
How This Plays Out in Practice
Saving 60% of a Stalled $400k Investment by Rebuilding Only What Was Broken
A family-owned Victorian manufacturer had an ERP migration stalled 18 months in, with staff running old and new systems side by side. We assessed every work-stream against three salvage tests. The configuration passed. The data migration approach failed two of the three, and the shop-floor integration failed all three, so we scrapped and rebuilt it. Data moved across in three rehearsed dress runs before the live cutover. The same rule applies to any legacy rebuild: keep what works, rebuild what does not.
Frequently Asked Questions
How much does legacy system modernisation cost in Australia?
Our two-week Modernisation Assessment costs A$9,500 to A$15,000 plus GST depending on the size of the system. Each rebuild phase is then fixed at A$25,000 to A$80,000 plus GST. Most mid-market systems need two to four phases, so a typical total is A$60,000 to A$250,000 plus GST. You approve each phase separately before it starts.
Who does the work on a legacy rebuild?
One of our CTOs reviews the system, plans the rebuild and leads the delivery. A small team of AI-driven developers does the build, using AI coding tools to read the old code, write tests and produce documentation quickly. The CTO reviews every phase before it goes live.
Should we rebuild our legacy system or replace it with SaaS?
Replace it with SaaS when a mainstream product covers almost everything the system does and your process is not a source of advantage. Rebuild when the system encodes how your business works differently from competitors, or when SaaS would force expensive workarounds. The assessment costs both options so the decision rests on numbers.
How does AI make legacy modernisation cheaper?
Most of the cost in a legacy rebuild goes on understanding the old code, writing tests and producing documentation. AI coding tools now do much of that first pass quickly, and senior engineers review and correct the output. McKinsey reported 40 to 50 percent faster modernisation timelines using gen AI. The saving goes into building and testing the new system properly.
Can you migrate a Microsoft Access database to the cloud?
Yes. Access databases are one of the most common systems we see. We move the data to a managed database such as PostgreSQL or Azure SQL and rebuild the forms and reports as a web application with proper user accounts, permissions and audit trails. Staff can then use it from any browser, and it can connect to your other systems.
Will our business keep running during the rebuild?
Yes. The old system keeps running while the new one takes over one module at a time. Data migration is rehearsed several times before go-live, and each cutover has a rollback plan.
Who owns the code after the project?
You do. The new system is built on mainstream open technologies, the code lives in your own repository and your own cloud account, and the documentation is written so another developer can take it over.
Get a Straight Answer on Your Legacy System
Book a call and tell us what the system does and what it runs on. We will tell you whether it is worth rebuilding, and what the first two weeks would look like.