iOS 12.1 (build 16B5089b) is an official Apple over-the-air update for the iPhone 5s (GSM), released on 2018-10-22T17:02:00Z. The update package is 417.55 MB. This is a delta (partial) update that requires 12.0 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: 26b36ecf50225e406bd5a47270a955d4545b1360.zip.