iOS 15.7.4 (build 19H321) is an official Apple over-the-air update for the iPhone 6s+, released on 2023-03-27T17:12:53Z. The update package is 2.34 GB. This is a delta (partial) update that requires 14.7 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: c4b663a82666412f58cc395eccbb08dc0625d54d.zip.