If your iPhone is set to install updates automatically, iOS 27 can arrive without you choosing a moment for it. Apple’s own description is blunt: when an update is available, iPhone downloads and installs the update overnight while charging and connected to Wi-Fi.
iOS 27 is free and lands on Monday, September 14, for iPhone 11 and later plus iPhone SE (2nd generation and later). Apple has not published a release time, so the first night your phone is charging on Wi-Fi after that is the window that matters if you have left the automatic setting on.
| Key fact | What Apple has published |
|---|---|
| Release date | Monday, September 14, 2026, free |
| Compatible iPhones | iPhone 11 and later, plus iPhone SE (2nd generation and later) |
| Automatic install conditions | Overnight, while charging and connected to Wi-Fi |
| Advance notice | Apple says automatic install gives notification beforehand |
| Minimum battery percentage | Not published |
| Minimum Wi-Fi speed | Not published |
| Release time on September 14 | Not published |
The two switches Apple describes, and the third one
Apple’s update article describes automatic updating as two separate things, which is the part most people miss. One handles the download. The other handles the install.
Don’t miss the best of The Mac Observer
Set us as a preferred source and our Apple reporting ranks higher in your Google Search results and Discover feed — one tap, no account changes.
| Setting | What Apple says it does |
|---|---|
| Automatic download | Downloads the update in the background, and you install it yourself |
| Automatic install | Installs overnight while charging and connected to Wi-Fi, with notification in advance |
| Security responses and system files | Covers updates that do not change the version number |
The third row is worth separating out because it is not a version upgrade at all. Apple describes it as a distinct setting for security responses and system files that leave the version number alone, so turning it off is a different decision from turning off iOS version upgrades.
Apple’s wording does not distinguish a point release from a major version upgrade, and Apple has published nothing specific to iOS 27 here. The article that carries all of this is dated December 5, 2025 and is written around iOS 18 and iOS 26, so the labels and the path may move when iOS 27 ships.
The manual route, in Apple’s order
If you would rather choose the moment, Apple’s published sequence puts two steps before Settings, and both are easy to skip.
- Back up your device using iCloud or your computer.
- Plug your device into power and connect to the internet with Wi-Fi.
- Go to Settings.
- Tap General.
- Tap Software Update.
- If an update is available, tap Download and Install, then follow the onscreen instructions.
Those steps follow Apple’s published description and may differ slightly once iOS 27 ships on September 14. Note what is not in them: Apple publishes no minimum battery percentage for a wireless update and no minimum Wi-Fi speed. The instruction is one sentence about power and Wi-Fi, and that is the whole of it.
If it does not work, Apple’s documented causes are narrow and worth knowing. VPN or proxy connections might prevent a device from contacting the update servers. Apps can be temporarily removed because the update needs space, and Apple says those apps are automatically reinstalled after installation completes. If the update never appears, Apple’s route is to update from a computer instead.
Why the timing choice is the whole decision
There is no undo. Apple publishes no downgrade path for a public release of iOS: no procedure, no warning against one, no acknowledgement of the question. The only place Apple describes returning to an earlier version is scoped to beta software, and even there it depends on a backup made before the upgrade and involves erasing the device.
So the decision point is before the install, not after, which is exactly why leaving automatic install switched on hands that decision to whichever night your phone happens to be charging.
Apple documents two things people notice afterwards. Battery life can be lower for a while, and Apple’s guidance is to wait a few days and then check again, because certain tasks related to the update continue in the background. A phone can also run warm, and Apple lists completing a software update, particularly to a major release, among the activities that change a device’s temperature.
Which iPhones this applies to
Every iPhone on Apple’s iOS 27 list, from iPhone 11 up to the new iPhone 18 Pro, can receive the update this way. The iPhone Duo is on the compatibility list too, though it does not reach buyers until October.
Apple Intelligence is a separate matter and a much shorter list: iPhone 16 and later plus iPhone 15 Pro and 15 Pro Max. An iPhone 11 through iPhone 15 Plus gets iOS 27 with none of it. Our iOS 27 release date explainer covers the feature split, and the event recap and our iPhone 18 Pro versus iPhone 17 Pro comparison cover the hardware side.
What Apple has not said
- No release time on September 14, so no way to know which night the automatic install would trigger.
- No statement on whether automatic install offers a major version upgrade on day one or later.
- No minimum battery percentage and no minimum Wi-Fi speed for a wireless update.
- No download size and no free-space figure for iOS 27.
- No downgrade path for a public release, in any form.
iOS 27 arrives Monday, September 14. If you want to choose when it installs, the setting to check is the automatic one, and the time to check it is before Monday night.
