iPadOS 11.3 (build 15E216) is an official Apple over-the-air update for the iPad 5 (WiFi), released on 2018-03-29T17:10:08Z. The update package is 677.39 MB. This is a delta (partial) update that requires 11.1 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: 7067d4c0f0bb691bbf57517cc03dc0c20160e48d.zip.