iOS 12.1.1 (build 16C50) is an official Apple over-the-air update for the iPhone 5s (GSM), released on 2018-12-05T18:10:16Z. The update package is 1.38 GB. This is a delta (partial) update that requires 11.0.1 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: 6033bb05174acb928fd96822f4f059cc782a3e33.zip.