Introduction: The great legacy reckoning

The pressure to modernize technology infrastructure and practices is constant, but recent events have made the task even more urgent.

The global IT outage of July 2024, triggered when a problematic update from security vendor CrowdStrike clashed with Microsoft’s widely-used software, dealt a blow to businesses worldwide, with estimates placing the damage to the Fortune 500 alone north of US$5 billion. The disruption proved especially problematic for firms with outdated legacy systems, such as airlines, which took longer to recover.

Even before this painful reminder of the need to boost resiliency, most systems were facing customer and market demands that differ vastly from the time they were built. “When you move beyond the boundaries of what was originally expected of a system, its ability to keep up with the pace of change comes into question,” says Ashok Subramanian, Head of Technology, Europe at Thoughtworks. “Challenges start to appear in terms of changes not happening fast enough, quality not being good enough, or customer experience failures.”