Apple’s WWDC26 Global Developers Conference officially kicked off today (June 9), and the earlier Keynote conference showcased a number of new features and operating systems. Among them, the compatibility between iOS 27 and Apple Intelligence, which users are most concerned about, was later disclosed.
According to information released by Apple, iOS 27 supports a large number of iPhones this time. As old as the iPhone 11 series and iPhone SE 2nd generation or above, all support iOS 27 upgrades.

However, if you want to use the new features of Apple Intelligence at the same time, the iPhone must be equipped with at least A17 Pro or newer generation chips, that is, the iPhone 15 Pro series released in 2023 at the latest.

As for the iPad and Mac platforms, in addition to the iPad mini with A17 Pro and the MacBook Neo with A18 Pro, iPads and Macs with M1 or newer chips are required to be compatible.
Short comment from Mobile Magazine: For old iPhone users, the iPhone 11, which was built 7 years ago, can still support the new version of iOS 27, which is quite convenient; and the new AI functions available on A17 Pro and above are also relatively loose.
Source: Apple