iOS 11.4 (build 15F5061d) is an official Apple over-the-air update for the iPhone 6s+, released on 2018-05-01T17:06:07Z. The update package is 214.99 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: 3a302e6a5e2d6e901c2dd5f6f0917afe343f5ccb.zip.