iOS 12.1 (build 16B5089b) is an official Apple over-the-air update for the iPhone SE, released on 2018-10-22T17:02:09Z. The update package is 418.93 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: 6c8e0e93e1655f8f9a1d383dde14899f47fa9734.zip.