How is an "incident" defined in ITIL 4?

In ITIL 4, an "incident" is defined as an unplanned interruption or reduction in the quality of a service. This definition highlights the unexpected nature of incidents, which differ from routine maintenance or upgrades that are pre-scheduled and controlled.

Incidents can lead to disruption in business processes, affecting the end-users' ability to access services as intended. Therefore, the focus within incident management is on restoring normal service operation as quickly as possible while minimizing impact on the business. This definition emphasizes the importance of responding to and managing occurrences that negatively impact the service experience.

The other answers refer to different situations that do not align with the definition of an incident in ITIL. A planned upgrade is a proactive change, scheduled maintenance refers to expected downtime for service improvements, and a potential service improvement is about future enhancements rather than responding to current disruptions.