Apple's iOS 27 update is compatible with the iPhone 11 and later, including the second-generation iPhone SE and newer models, but only certain newer iPhones support the full set of features.
Apple's latest software carries over the same device compatibility list as iOS 26, so no iPhones have been dropped this year. However, iOS 27's headline additions, such as the new Siri AI and expanded Apple Intelligence features, depend on hardware, which effectively splits supported iPhones into three separate tiers.
From the top, the iPhone 17 Pro, iPhone 17 Pro Max, and iPhone Air are the only current models that support every new Siri AI feature in iOS 27. These devices run Apple's most advanced on-device Apple Intelligence model, which enables higher accuracy for speech-to-text dictation and the ability to customize the expressiveness and pace of Siri's voice.
The reason those two features are so exclusive basically comes down to memory. The on-device model powering them requires a minimum of 12GB of RAM, which only the iPhone 17 Pro models and iPhone Air currently offer. Meanwhile, the iPhone 17 and iPhone 17e include only 8GB.
Believe it or not, that threshold will likely matter again next year when Apple releases fresh iPhone 18 series models as part of its new split-launch cycle. According to supply chain analyst Ming-Chi Kuo, the iPhone 18 and iPhone 18e will include 9GB of RAM, which is enough for standard Apple Intelligence features, but it's still short of the 12GB needed for the top-tier features. Meanwhile, the iPhone 18 Pro, iPhone 18 Pro Max, and foldable "iPhone Duo" likely all get 12GB of RAM, so they'll be able to run all features.
Below the top tier, the full iPhone 16 lineup (including the iPhone 16e) plus the iPhone 15 Pro and iPhone 15 Pro Max support standard Siri AI and Apple Intelligence features. That includes the redesigned Siri interface and new standalone Siri app, which combine personal context, onscreen awareness, and web knowledge for more natural conversations and in-app actions, plus new photo-editing tools like Extend and Spatial Reframing.
Elsewhere, everything else, from the iPhone 15 and iPhone 15 Plus down to the iPhone 11, gets iOS 27 without Apple Intelligence or the new Siri. Older devices aren't left entirely out in the cold, though – iOS 27 includes an upgraded CPU scheduler designed to help all iPhones handle tasks more efficiently, as well as rebuilt system search and Liquid Glass refinements.
One regional caveat is worth noting: Siri AI won't be available on any iPhone or iPad in the European Union at launch, due to regulatory constraints enforced by the bloc's Digital Markets Act (DMA). It will be available in the EU in macOS 27 Golden Gate, however. Apple is working with EU regulators to find a solution.
iOS 27 was released on September 14 and is available to download now.
