iOS 11.4 (build 15F5049c) is an official Apple over-the-air update for the iPhone 6s+, released on 2018-04-16T17:08:22Z. The update package is 219.08 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: 9395fac1b1b1a29120770ad0b35a0648dea83ee7.zip.