iPadOS 9.9.13.5 (build 17F75) is an official Apple over-the-air update for the iPad Pro 4 (12.9-inch, WiFi), released on 2020-05-18T17:18:54Z. The update package is 3.16 GB. This is a full OTA update that can be applied from any compatible base version. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: 82e23e64189ad4d6a4e05ffb24c04b071643d054.zip.