Since September 14, 2026, the Software Update screen in iPhone Settings shows two updates. The one set as default at the top is iOS 26.7, and the one attached separately below is iOS 27.

Both contain security fixes, and the iPhones that can get them are the same. Where they split is whether your device can use the new Siri AI and when it becomes available in Korean.

Announcement image for the release of iOS 27 and other 27-series OSes Announcement image for the release of iOS 27 and other 27-series OSes — Source: Apple

Two update paths

Number of security fixes in iOS 27 and iOS 26.7 Number of security fixes in iOS 27 and iOS 26.7 — Source: self-rendered based on Apple Support security documents

Apple released iOS 27 and iOS 26.7 together on September 14. iOS 26.7 contains only security fixes with no new features, and it’s shown by default on the Settings screen. iOS 27 is attached separately lower on the same screen as an Upgrade to iOS 27 item.

Counting the CVE numbers in Apple’s security documents, iOS 27 has 126 and iOS 26.7 has 82, with 75 numbers appearing in both. 51 fixes appear only in the iOS 27 document, so iOS 27’s security fix coverage is broader.

Neither document carries wording that there were reports of active exploitation. That means neither is an emergency patch you need to rush to install.

Apple hasn’t said how long it will keep shipping security updates for iOS 26.

Coverage by device

Siri AI reading on-screen content and answering Siri AI reading on-screen content and answering — Source: Apple

iOS 27 can be installed on iPhone 11 and later, the same as iOS 26, including the iPhone SE 2nd and 3rd generation.

iPadOS 27 covers the 12.9-inch iPad Pro 4th generation, 11-inch iPad Pro 2nd generation, iPad Air 4th generation, iPad 9th generation, iPad mini 6th generation, and later. The 12.9-inch Pro 3rd generation, 11-inch Pro 1st generation, Air 3rd generation, iPad 8th generation, and mini 5th generation only get up to iPadOS 26.7.

iPhone iOS 27 Siri AI · Apple Intelligence
11, 12, 13, 14 Can install Not supported
SE 2nd and 3rd gen Can install Not supported
15, 15 Plus Can install Not supported
15 Pro, all 16 models, 17 Can install Supported (up to 8GB)
17 Pro, 17 Pro Max, Air Can install Supported (up to 14GB)

Siri AI and Apple Intelligence run only on iPhone 15 Pro and later. The iPhone 15 and 15 Plus, released the same year, fall on the other side of this line.

Apple’s support document lists the storage Apple Intelligence takes up as up to 8GB, and up to 14GB for the iPhone 17 Pro, 17 Pro Max, and Air. That’s because a larger on-device model goes into the 17 Pro and Air; this model requires 12GB or more of unified memory, so the regular iPhone 17 isn’t covered. The more expressive Siri voices and advanced dictation are supported only with this model.

On 15 Pro and later devices that are tight on storage, freeing up Apple Intelligence’s 8GB (14GB on the 17 Pro and Air) before installing avoids low-storage warnings.

Conditions for using Siri AI

Conversation screen with Siri AI Conversation screen with Siri AI — Source: Apple

The centerpiece of iOS 27 is Siri AI, rebuilt on a new architecture. It reads personal context in Messages, Mail, and Calendar, understands what’s on screen, and carries out tasks across apps for you, such as adding a booking you received in Messages to your calendar.

Apple said the feature runs on next-generation Apple Foundation Models built with Google, and that it protects personal information with on-device processing and Private Cloud Compute.

[Language] English beta on September 14, Korean to be added in October

[Waitlist] Request it under Settings → Siri → Try Siri AI (Beta); approval time varies by account

[Usage] Daily limits on features that use Private Cloud Compute, to be expanded on some iCloud+ plans

[Age] Not available to accounts under 13

Apple Intelligence itself already includes Korean among supported languages. The condition is that the device language and Siri language must be the same supported language, so according to Apple’s support document, setting both to English lets you request the English beta in September too.

The regional restriction doesn’t apply to Korea. Siri AI isn’t offered at launch on iPhone, iPad, and Apple Watch in the EU or in China.

Korean Siri AI comes in October, and eligible devices are iPhone 15 Pro and later

Speed improvement figures

iOS 27 speed improvements iOS 27 speed improvements — Source: self-rendered based on figures announced in Apple Newsroom

The change that also applies to the iPhone 11–14 and 15/15 Plus, which can’t use Siri AI, is speed. Apple announced that in iOS 27, app launches are up to 30% faster, loading a just-taken photo in the Photos app is up to 70% faster, and AirDrop transfers are up to 80% faster.

All three are maximums, so the improvement you notice may be smaller depending on the device and situation. Apple didn’t publish per-model figures.

Other notable changes include website change notifications in Safari, revamped parental controls (approval requests for new websites, daily usage allowances), and a call context feature that surfaces verification codes and booking numbers during calls with businesses.

Battery and heat right after installing

Concept image of background re-indexing right after an update Concept image of background re-indexing right after an update — Source: concept image · self-generated with agy

The most common complaints after the iOS 27 release are battery drain and heat. Apple explains that right after a major update, a device has to finish indexing data and files for search, downloading new assets, and updating apps in the background, and iOS 27 re-indexes the entire device for Siri AI, so that load is heavier than a usual major update.

9to5Mac reported that this re-indexing can go on for several days. If drain is still heavy after that period, it’s time to check which apps are using the most power under Settings → Battery.

Summary of how to choose

Summary of how to choose between iOS 27 and iOS 26.7 Summary of how to choose between iOS 27 and iOS 26.7 — Source: summary of the article · self-rendered

On the iPhone 11–14 and 15/15 Plus, Siri AI isn’t supported even after installing iOS 27, so the remaining differences are the speed improvements and 51 security fixes. Even on 15 Pro and later devices, using Siri AI in Korean means waiting for language support in October.

Sources