iOS 9.9.11.2.1 (build 15C153) is an official Apple over-the-air update for the iPhone 5s (GSM), released on 2017-12-13T18:11:10Z. The update package is 1.54 GB. 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: 74535462ad4bc0d37d4125fd4d2e7f94594c97d3.zip.