iOS 9.9.11.2.1 (build 15C6153) is an official Apple over-the-air update for the iPhone 8 (GSM), released on 2017-12-13T18:03:13Z. The update package is 1.82 GB. This is a full OTA update that can be applied from any compatible base version. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: 5075440590e9db1e4f96984c8d8d3283824345ea.zip.