The absence of iOS 18 on a device can be attributed to several factors related to device compatibility, software release schedules, and user configuration. Generally, a new major iOS release like iOS 18 only supports a specific range of iPhone and iPad models. Devices older than this range may lack the hardware capabilities required to run the new operating system efficiently, leading to non-compatibility. For example, if iOS 18 requires a specific processor or amount of RAM, devices lacking those specifications will not be eligible for the update.
Access to the newest iOS version is beneficial, because it often includes performance improvements, security patches, and access to new features designed to improve the user experience. Software updates are also important to protect the device from emerging security threats. Historically, Apple has provided several years of software support for its devices, but eventually, older models are excluded from receiving updates as the hardware becomes outdated.
