iOS 27 retains the same device compatibility list as iOS 26, meaning the iPhone 11 and all subsequent models, including the second-generation iPhone SE, are eligible for the update. However, Apple is dividing the experience into several tiers depending on the hardware.

At the top tier, the iPhone 17 Pro, iPhone 17 Pro Max and iPhone Air are the only three current models that support the full range of new Siri AI features at the launch of iOS 27, excluding the newer iPhone 18 Pro, iPhone 18 Pro Max and iPhone Duo.

These devices run a more powerful Apple Intelligence model directly on the device. This allows Siri to recognize speech more accurately during dictation, while also letting users customize how the assistant speaks, including its speed and level of expressiveness.

The key factor is RAM. The on-device AI model behind these features requires at least 12GB of memory. The iPhone 17 Pro, iPhone 17 Pro Max and iPhone Air meet that threshold, while the iPhone 17 and iPhone 17e have only 8GB.

The next tier includes the entire iPhone 16 lineup, including the iPhone 16e, as well as the iPhone 15 Pro and iPhone 15 Pro Max. These devices support standard Apple Intelligence and Siri AI features.

Users get the redesigned Siri interface and a standalone Siri app that combines personal context, information displayed on the screen and knowledge from the web. These features are designed to make interactions more natural and allow Siri to perform tasks directly within apps.

iOS 27 also introduces photo-editing tools including Extend and Spatial Reframing.

The iPhone 15, iPhone 15 Plus and older models going back to the iPhone 11 still receive iOS 27, but do not support Apple Intelligence or the new Siri AI features.

Apple says these devices will still benefit from system improvements. iOS 27 is designed to help older iPhones handle tasks more efficiently, while also introducing a rebuilt search system and several changes to the Liquid Glass interface.

So while Apple has not removed any models from the upgrade list, it continues to create a significant divide between generations based on hardware capabilities. Owners of older iPhones can still run the latest version of iOS, but they will not have access to the AI features Apple is positioning as a centerpiece of the operating system.

Another notable limitation applies in Europe. Siri AI is not available on iPhones and iPads in the European Union at the launch of iOS 27 because of regulatory requirements related to the Digital Markets Act (DMA). Apple says it is working with EU regulators to find a solution.

Siri AI is still expected to be available on macOS 27 Golden Gate in the region.

The 12GB RAM requirement for the most advanced AI features could also shape the experience on future iPhone generations. According to supply-chain analyst Ming-Chi Kuo, the iPhone 18 and iPhone 18e are expected to come with 9GB of RAM, while the iPhone 18 Pro, iPhone 18 Pro Max and Apple's foldable iPhone are expected to feature 12GB.

If those projections prove accurate, Apple could continue to differentiate AI capabilities between iPhone models rather than simply determining access based on whether a device can run the latest version of iOS.

To install iOS 27, users with an iPhone 11 or newer can go to Settings > General > Software Update.

Du Lam