Which of the following best describes a legacy application?

A legacy application is best described as an outdated system that might still be crucial for operations. This definition is accurate because legacy applications often represent systems that have been in use for many years, built on older technologies or programming languages. Despite their age, these applications can be integral to business processes, holding valuable data or functionalities that are not easily replicated in newer systems.

Organizations may face challenges with legacy applications, such as difficulty in finding knowledgeable support or integration issues with modern applications, but the importance of these systems in day-to-day operations often compels businesses to continue using them. Such applications frequently require careful management and consideration, as replacing them can be a significant task involving risk to business continuity.