A legacy system is an old or outdated method, technology, computer system, or application program that is still in use. It may be based on outdated technologies, but it is critical to day-to-day operations. Legacy systems can include computer hardware, software applications, file formats, and programming languages. While the term "legacy" may imply that a system is out of date or in need of replacement, a legacy system can continue to be used for a variety of reasons. Some organizations may keep a legacy system because it still provides for the users needs, or because the costs of redesigning or replacing the system are prohibitive. However, legacy systems can cause a myriad of problems, such as exorbitant maintenance costs, data silos that prevent integration between systems, lack of compliance to governmental regulations, and reduced security. Companies can identify they are using a legacy system or application by assessing diverse aspects, such as whether the system is no longer updated, heavily patched, or not possible to scale. The decision to replace a legacy application or system comes down to business requirements, and for many organizations, a legacy system may not necessarily need to be replaced if the technology still adequately supports its processes.