iOS 15.7.3 (build 19H307) is an official Apple over-the-air update for the iPhone 6s, released on 2023-01-23T18:49:09Z. The update package is 3.05 GB. This is a delta (partial) update that requires 13.4 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: a26e958a986740a3ea125ac1fa5817799708fe38.zip.