A developer’s viewpoint - why modernising software makes sense

Ben Hopper , Software Development Team Leader, and Jahanzeb J , Senior Developer at Propel Tech, talk all things modernisation vs. rebuild...

When we talk about software modernisation, the conversation usually centres on new functionality, budgets, and ROI. But developers see a different side of the story - one that’s all about long-term value, efficiency, and keeping systems working smarter for the teams who rely on them. Ben and Jahanzeb explain…

Modernising vs rebuilding: it’s not just about cost

Ben: “There’s a common assumption that building software from scratch is faster, cleaner, and more future-ready. Sometimes that’s true, but not always. If an existing system still does its core job, modernising it can unlock huge value with far less disruption. You keep what works, fix what doesn’t, and make it easier to evolve.”

“Modernisation isn’t just a tech upgrade, it’s a way to make sure your software keeps pace with your business. From a developer’s perspective, the best systems are the ones that are easy to understand, easy to improve, and built to last.”

Jahanzeb: “A lot of people think code modernisation means rewriting everything either partially or completely. But often, it’s about making gradual improvements. Refactoring what’s already there, introducing better tools or practices, and building on what works instead of throwing it all away.”

Real-world value from phased modernisation

Jahanzeb: “We were working with a legacy system built on a custom PHP 5.3 framework that had supported the business reliably for years. Rewriting it from scratch would have been risky, time-consuming, and expensive. Instead, we modernised it gradually.

“Our first step was upgrading the PHP version. We carefully updated deprecated code while ensuring stability. Once that was complete, we began migrating to cloud hosting in phases, avoiding disruption and improving reliability and scalability along the way. In the end, this approach gave us all the benefits of a modern platform without the risks of a full rebuild.”

Clean code = fast teams

Ben: “Old systems can come with messy, legacy code. It might ‘work,’ but it slows everything down, from bug fixes to feature updates. Modernisation gives us the opportunity to improve code quality, introduce proper tests, and bring structure to systems that have grown messy over time. For developers, clean code isn’t just about pride, it’s about making future change safer, faster, and more reliable.”

Maintenance matters

Ben: “One of the biggest risks in established software is false confidence. Just because a system hasn’t fallen over doesn’t mean it’s secure, supported, or easy to update. Modernisation helps bring platforms back into a space where they’re maintainable, up-to-date, patched, and ready for whatever comes next, including AI.”

When is modernisation better than a rebuild?

Jahanzeb: “Any system that has been running for a while and consistently meeting business needs is usually a better candidate for modernisation. In many cases, the cost and risk of a complete rebuild outweigh the benefits. Even if a rebuild brings slightly better performance, a well-executed modernisation can offer very similar value - faster and with less risk.”

Ben: “Sometimes, a rebuild is the right move, especially when a system lacks tests, is blocking growth, or is too far gone. But in many cases, thoughtful, phased modernisation gives you more control, less risk, and less pressure on internal teams.”

Making systems AI-ready

Jahanzeb: “The first step to making a system AI-ready is understanding how its data could be leveraged. In many cases, AI can sit behind the scenes, learning from the data and improving the user experience without needing to replace the core system.”

Want to understand the case for modernising vs replacing software? Read our latest insight, 'Making the right call for your business software'.