iPadOS 11.3 (build 15E216) is an official Apple over-the-air update for the iPad mini 3 (WiFi), released on 2018-03-29T17:06:58Z. The update package is 614.59 MB. This is a delta (partial) update that requires 11.2.1 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: 8f7f94d2d915c34266e394a2e9b899d3b8388331.zip.