iOS 9.9.12.1 (build 16B5059d) is an official Apple over-the-air update for the iPhone 8 Plus (GSM), released on 2018-09-18T17:20:18Z. The update package is 2.42 GB. This is a full OTA update that can be applied from any compatible base version. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: 7d487d91d67e2e4b2aefcfc2daa4242d97e74e5c.zip.