fixed identification code, the IMEI. A telephone reported stolen can have its IMEI blocked by networks, preventing them from being used as mobile devices. iOS offers a similar "Activation Lock" feature via the "Find My iPhone" security software, where a device can be remotely prevented from operating (even after it has been erased), protected by the owner's Apple ID. Devices that have a strong dependency on online services in order to function may be bricked after services are discontinued by the manufacturer, or some other technological factor (such as expired security certificates or other services quietly becoming unavailable) effectively prevents them from operating. This can happen if the product has been succeeded by a newer model and the manufacturer no longer wishes to maintain services for the previous version, or if a company has been acquired by another or otherwise ceases operations, and chooses not to, or is no longer able to maintain its previous products. For example, Apple dropped support for OS X El Capitan in October 2018, and on 30 September 2021 the built-in security certificate expired, rendering users unable to connect to or use any iCloud services. The security certificate issued with the final updates of OS X Sierra and High Sierra have expired as of 20 May 2022. The practice has especially been scrutinized within the Internet of things and smart home markets. Bricking in these cases have been declared a means to enforce planned obsolescence. References Computer jargon