Over time, new technologies emerge that provide more advanced software and computing functionality, leading businesses to invest in upgrading their applications and systems. Legacy IT refers to an outdated operating system or software application that’s still being used by an organization because it supports a critical business function. It includes applications that developers no longer update, maintain, or support (which may contain vulnerabilities), systems or applications that are no longer sold or utilize obsolete technologies, and hardware that can no longer support a company’s software systems. These factors can make legacy IT difficult and costly to maintain.