iOS 17 will not download to iPad A1673.

Your first generation iPad Pro 9.7" fundamentally does not support iPadOS 17.

For information, here is a list of the highest version of iOS supported by the older models of iPad (for simplicity - “generations” are shortened to a number) that are restricted in their ability to be updated:

32-bit devices (obsolete)

iPad1 - iOS 5.1.1

iPad2, iPad3 and iPad mini1 - iOS 9.3.5 (WiFi Only models), iOS 9.3.6 (WiFi & Cellular)

iPad4 - iOS 10.3.3 (WiFi Only), iOS 10.3.4 (WiFi & Cellular)

64-bit devices

iPad Air1*, iPad mini2 and iPad mini3* - iOS 12.5.7

iPad Air2, iPad mini4 - iPadOS 15.8.2

iPad5, iPad Pro (9.7"/12.9" first generation) - iPadOS 16.7.7

(*) obsolete

Newer models are all able to be updated to the current version - iPadOS 17.4.1

• iPad Pro 12.9" (2nd generation and later)
• iPad Pro 11" (1st generation and later)
• iPad Pro 10.5"
• iPad Air (3rd generation and later)
• iPad (6th generation and later)
• iPad mini (5th generation and later)

An unit running 16.7.7 isn't capable of 17 or above.

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