iOS 12.1 (build 16B5059d) is an official Apple over-the-air update for the iPhone 8 (GSM), released on 2018-09-18T17:20:18Z. The update package is 534.28 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: dba7a79b078300009dcb1df99c965dce6855397e.zip.