iOS 12.1.2 (build 16D5024a) is an official Apple over-the-air update for the iPhone 5s (GSM), released on 2018-12-10T18:09:08Z. The update package is 255.96 MB. This is a delta (partial) update that requires 12.1.1 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: 52bcadb2a1f18e229c83ffb4dd08e076f39d49db.zip.