“According to reports, Apple made changes to the firmware of some of its processors in the fall of 2020 – but the alterations were reportedly never announced and apparently made mid-production. Spotted by Twitter user Andrew Pantyukhin, the changes were made to update the Secure Enclave component on the A12, A13, and S5 processors in Apple’s devices in the fall of 2020.
As its name suggests, the Secure Enclave is a secure co-processor, that handles keys and other sensitive information such as bio-metrics. It is isolated from the main processor in order to provide an extra layer of security. The Secure Enclave is shipped with certain versions of the iPhone, iPad, Mac, Apple TV, Apple Watch and HomePod”.