iOS 11.3 (build 15E5211a) is an official Apple over-the-air update for the iPhone X (GSM), released on 2018-03-12T17:05:43Z. The update package is 250.22 MB. This is a delta (partial) update that requires 11.3 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: a5fdfc22c5a6b37cc5822e2bd82dfa6503500c64.zip.