# You have a system nobody wants to touch — Alfaveo

> A practical guide to modernising without the risk of a full replacement

Source: https://alfaveo.com/guides/legacy

## You have a system nobody wants to touch

A practical guide to modernising without the risk of a full replacement

There is a system. It works, mostly. Nobody knows exactly how it works anymore. The person who built it left years ago. Every time someone wants to change something, it takes months, costs more than expected, and introduces a new bug somewhere else. So nothing gets changed, and the workarounds multiply.

This is a solvable problem. But the way most businesses try to solve it is also the way most of them make it worse.

### Why replacing it is usually the wrong first move

The instinct is to replace the legacy system with something modern. In most cases this is the most expensive and most risky answer, and it often does not solve the actual problem. Legacy systems become problems not because the technology is old, but because the business has changed and the system has not. When you try to replace one, you discover nobody can fully specify what it does, undocumented behaviours, edge cases nobody wrote down, data in mystery formats. Over 60% of full replacement projects run significantly over time and budget, and a meaningful proportion are abandoned.

The safer, faster, and usually cheaper path is to wrap it.

### What wrapping means in practice

Wrapping means building modern tooling around the legacy system, handling the processes that have outgrown it, improving the interfaces people use every day, and connecting it to other systems without touching the core. Over time, as trust is established, parts of the legacy system can be migrated incrementally, in stages small enough to be tested and validated.

- It delivers value faster, the first piece of new tooling can run in three to five weeks, with no big-bang cutover.
- It is lower risk, each stage is small enough to test and reverse; the core is not touched until there is high confidence.
- It reveals the real requirements, you learn what the business actually needs by watching how people use what you build.

### How to start

- Map what the legacy system actually does, including the undocumented behaviours and the manual steps people use to work around it.
- Separate what works from what does not, keep the reliable parts, target the actively painful ones first.
- Start with the edge processes, the things handled in spreadsheets around the system. Lowest integration risk, immediate value.
- Connect to the legacy system carefully, reverse-engineer the data model so data flows automatically without depending on undocumented behaviour.
- Migrate incrementally, small, tested, parallel-run stages. There is no deadline; some components may never need to migrate.

### The data question

Legacy systems usually contain years of historical data the business relies on. Make the legacy database readable from the new layer (without writing to it) so historical records stay accessible from day one. Do not try to migrate historical data at the start, get the new system running on new data first, then migrate history later, in stages.

### What this is worth

The direct cost of a legacy system, expensive support contracts, slow change processes, compounding integration costs, runs to £50,000 to £200,000 a year for most businesses. The indirect cost is harder to see: the growth that cannot happen because the system cannot support it.

The signal that this is your biggest problem: you have said the words “we cannot change that” about a system in the last six months. If a system cannot be changed to fit how the business needs to work, it is a ceiling on growth, and that ceiling gets lower every year.

### About Alfaveo

Alfaveo builds custom software that connects to your existing systems and handles the processes they were never designed for. We start with a working prototype in 10 business days, real UI, real data, real workflow, so you can see exactly what you are getting before committing to a full build.

If what you have read here describes your situation, the most useful next step is a 30-minute conversation. No proposal, no pitch, just an honest assessment of what is worth fixing first and roughly what it would take.

Book a 30-minute conversation