iOS 12.1 (build 16B92) is an official Apple over-the-air update for the iPhone 5s (GSM), released on 2018-10-30T17:16:30Z. The update package is 1.28 GB. This is a delta (partial) update that requires 11.3.1 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: fb2190c02b682fe28dec8abf23462a04dd5389d7.zip.