iOS 27 becomes a free update for a long list of iPhones on Monday, September 14, and the oldest model that qualifies is the iPhone 11 and the iPhone SE (2nd generation), not the iPhone 12 that keeps getting repeated. Six questions cover most of what people are typing into search this week, and Apple’s own pages already answer every one of them.
With iPhone 18 Pro pre-orders now open and iOS 27 two days from release, the timing questions are no longer hypothetical. The answers below use only what Apple has published on its iOS, Apple Intelligence and support pages, not community guesswork about install times or beta problems Apple has never quantified.
| Item | What Apple publishes |
|---|---|
| iOS 27 release | Free update, Monday, September 14, 2026 |
| Oldest supported iPhone | iPhone 11 and iPhone SE (2nd generation) |
| iPhone 18 Pro on sale | Friday, September 18, 2026 |
| Downgrade path from iOS 27 | Not published for public releases |
| Post-update battery drain | Documented as temporary, support article 120745 |
Is iOS 27 free, and when does it arrive
Apple’s iOS page states iOS 27 is available starting September 14, a free software update with no separate purchase or subscription attached to installing it. Every device on the compatibility list receives it the same day, in every country where Apple sells the operating system.
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Which iPhones can install iOS 27
Apple’s own compatibility list starts at the iPhone 11 and the iPhone SE (2nd generation), not the iPhone 12 that keeps circulating as the cutoff. Nothing was dropped from last year’s list.
- iPhone 11, iPhone 11 Pro, iPhone 11 Pro Max
- iPhone 12 mini through iPhone 12 Pro Max, iPhone 13 mini through iPhone 13 Pro Max
- iPhone 14, iPhone 14 Plus, iPhone 14 Pro, iPhone 14 Pro Max
- iPhone 15, iPhone 15 Plus, iPhone 15 Pro, iPhone 15 Pro Max
- iPhone 16e, iPhone 16, iPhone 16 Plus, iPhone 16 Pro, iPhone 16 Pro Max
- iPhone 17e, iPhone 17, iPhone 17 Pro, iPhone 17 Pro Max, iPhone Air
- iPhone 18 Pro, iPhone 18 Pro Max, iPhone Duo
- iPhone SE (2nd generation) and later
iPhone Duo is on that list too, though Apple’s own press release confirms it ships in October on iOS 27.1, a point release rather than the iOS 27.0 build everyone else installs September 14.
Do you need to update before using a new iPhone 18 Pro
Apple has not published a line stating iPhone 18 Pro ships with iOS 27 already installed, but its own dates settle the practical question. iOS 27 becomes available September 14, and iPhone 18 Pro does not reach buyers until September 18, four days later. Any unit sold from launch day arrives running the software Apple has already shipped, with no separate update required just to start using the phone.
Why does your phone feel warm or drain faster right after updating
Apple documents both as expected, short-term behavior rather than a fault. Support article 120745 covers battery drain following a software update, and support article 118431 covers a device running warm afterward while background tasks such as re-indexing and app optimization finish. Neither article gives a timeframe for when that settles down.
Can you go back to iOS 26 if you change your mind
Apple has published no downgrade procedure for iOS 27 as a public release. That silence is itself the answer: there is no Apple-supported route back to iOS 26, and no third-party tool claiming otherwise is something this site will describe or recommend.
| Question | What Apple says |
|---|---|
| Ships already on iPhone 18 Pro | Not stated directly, but timing confirms it by September 18 |
| Warmth and battery drain after updating | Documented as temporary, no end point given |
| Downgrade route to iOS 26 | No procedure published |
What Apple has not said
Apple has not published an install-time estimate for iOS 27, has not confirmed a specific box-contents statement about iPhone 18 Pro’s software state on September 18, and has not said whether a downgrade tool will ever exist for this release. Each stays open until Apple’s own support pages address it directly.
As of September 12, 2026, iOS 27 is two days from its September 14 release, Apple’s own event recap lists everything announced alongside it, and iPhone 18 Pro itself ships four days later on September 18. The next confirmation worth watching for is Apple’s own iOS 27 release notes, published once the update goes live.
