iOS 11.2.5 (build 15D60) is an official Apple over-the-air update for the iPhone 5s (GSM), released on 2018-01-23T18:29:43Z. The update package is 451.37 MB. This is a delta (partial) update that requires 11.1 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: 56ebee50b2306d7b1c795e9c0a62c28d614415e2.zip.