Challenges with an outdated tech stack: Why modernising legacy tech is the key to innovating in retail

The retail landscape in the UK is constantly changing - now more so than ever, with the prevalence of AI and the threat from cyber attacks. From shifting consumer confidence and the rise of disruptive new players like Temu and Shein, to the demand for personalised experiences and the growing importance of digital security, retailers are navigating a complex environment. Underneath many of these challenges lies a significant hurdle: legacy software.

Many retailers are grappling with ‘untidy tech stacks’ – systems that have accumulated over time, with more and more layers and complexities added. This isn't just a matter of digital clutter; it's a fundamental blocker to innovation and business growth. The inherent fragility and complexity often found in intertwined, outdated systems. 

Imagine the difficulty in pursuing innovation or even maintaining efficient operations when a seemingly straightforward process, like processing a basic product order, has to navigate through a dozen different, disconnected systems. This complexity underscores the significant challenges posed by legacy technology.

Keeping up with customer expectations

This burden of legacy tech significantly hinders a retailer's ability to deliver on modern customer expectations. In 2025, personalisation is key, with 87% of shoppers* expecting it in return for their data. Achieving true personalisation requires a unified view of the customer, which is something notoriously difficult to attain when data is siloed across disparate, aging systems. Loyalty schemes, now used by a staggering 99% of shoppers*, offer rich data insights for retailers However, extracting and leveraging this information effectively is often hampered by outdated infrastructure. You can only truly drive loyalty with a modernised platform and a unification of technology.

The challenge of AI adoption

The limitations of legacy systems also stifle the adoption and effective use of innovative technologies, such as AI. Whilst AI holds immense potential for the retail sector and for personalising customer experiences, its implementation is often complicated by the inability to seamlessly integrate with older platforms. Similarly, the impressive 30% annual growth in social commerce compared to the 10% in traditional ecommerce highlights a missed opportunity for retailers whose legacy systems aren't agile enough to adapt to these new channels. Even optimising logistics and delivery, as seen with the rise of rapid same-day deliveries, becomes a greater challenge (or impossible) without modern, integrated systems.

Staying secure

Digital security has been brought sharply into focus by the recent attacks on major high street retailers. The impact of these attacks are often exacerbated by outdated infrastructure. 

Relying on legacy and outdated systems presents a significant security risk. These older infrastructures often lack the robust security features and regular updates found in modern platforms, creating vulnerabilities that cybercriminals can readily exploit. Consequently, retailers relying on such systems become more prone to sophisticated cyber attacks, increasing the likelihood of data breaches that can expose sensitive customer information like payment details and personal addresses, ultimately leading to financial losses, reputational damage, and a loss of customer trust.

Evolution, not revolution

The path forward in modernising a legacy tech stack is not necessarily a disruptive overhaul with business operations shutting down. It is important for retailers to have a deep understanding of the business’ operating model. When it comes to changing the operating model, a revolution rarely works. The systems must evolve step-by-step towards a vision -  an evolution, not revolution.

By employing techniques like Wardley mapping and value stream mapping, retailers can gain a deep understanding of their current systems and identify the next valuable increment that they need to take on the path to modernisation.

Whilst the retail sector faces numerous external pressures, the internal challenge of legacy technology looms large. Overcoming this burden isn't just about tidying up; it's about unlocking the potential for genuine personalisation, embracing new technologies, enhancing security, and ultimately, future-proofing the business. For retailers to truly thrive in this evolving retail landscape, addressing the ‘untidy tech stack’ must move from a background issue to a strategic priority.

Codurance have worked with a range of retailers to deliver software modernisation solutions. Read our retail case studies to learn more about how we helped.

If you’re looking to explore legacy modernisation for your business, get in touch here.

*Source: Savvy Shopper Panel, Savvy Marketing 2025