According to cnet.com

iPad

iPad Mini

iPad Mini 4

iPad 3

iPad Air 2

What iPads are compatible with iOS 11?

iOS 11 is compatible with 64-bit devices only, meaning the iPhone 5, iPhone 5c, and iPad 4 do not support the software update.

iPad

• 12.9-inch iPad Pro (first-generation)
• 12.9-inch iPad Pro (second-generation)
• 9.7-inch iPad Pro.
• 10.5-inch iPad Pro.
• iPad (fifth-generation)
• iPad Air 2.
• iPad Air.
• iPad mini 4.

Can iPad be updated to iOS 11?

iOS 12, the latest major update to Apple’s operating system for iPhone and iPad, was released in September 2018. All the iPads and iPhones that were compatible with iOS 11 are also compatible with iOS 12; and because of performance tweaks, Apple claims that the older devices will actually get faster when they update.