iOS 8.1 (build 12B411) is an official Apple over-the-air update for the iPhone 5s (GSM), released on 2014-10-20T17:59:09Z. The update package is 117.52 MB. This is a delta (partial) update that requires 8.0.1 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: 49d1431e03d7fef2035e16de6452e422cdef64ee.zip.