iOS 27 is out: does your app need an update?

Your iPhone app almost certainly still works on iOS 27, which Apple released on 14 September 2026, but you should test it now and plan an update before spring 2027. Apple has made the newest SDK mandatory for App Store uploads every April: the iOS 18 SDK in April 2025 and the iOS 26 SDK from 28 April 2026. If that pattern holds, you'll need to build with the iOS 27 SDK to ship any update from around April 2027, and rebuilding with a new SDK often exposes layout and behaviour changes.

So there's no emergency. But there is a deadline, and the cheapest time to handle it is before it's urgent.

What changes for apps in a new iOS release

Each major iOS version does three things that can affect your app:

• It changes how existing features behave, like permissions, notifications or background tasks.

• It deprecates older APIs, which keep working for a while and then stop.

• It adds new capabilities users start expecting, like widgets, Siri integration or new privacy prompts.

iOS 27 focuses on Apple Intelligence and Siri, including a rebuilt Siri with its own app, along with new child safety and parental control features. Most business apps won't break because of these. But apps that handle voice, messaging, family accounts or content for younger users should check how the new features interact with them.

What to test this month

Install iOS 27 on at least one test device and run through the flows that make money or keep customers:

• Signup and login, including passwords, one-time codes and Sign in with Apple

• Checkout and payments

• Push notifications, both receiving and tapping into the right screen

• Camera, photo library and location permissions

• Anything that runs in the background, like uploads or location tracking

• Deep links from emails and ads

Test on the phones your customers actually use

Your analytics or App Store Connect shows which iOS versions and devices your users run. Test on the most common ones. The newest iPhone on a developer's desk is the least likely phone to show a problem. Many customers keep phones for four or five years, so an older, smaller iPhone often finds problems a new one hides.

This is also a good moment to review your minimum supported iOS version. Supporting very old versions means more testing and more workarounds for every update. If only a tiny share of your users are on an old version, raising the minimum can make every future update cheaper. Check the numbers before deciding, and give those users a heads-up.

Watch for visual problems too. Apple's Liquid Glass design, introduced in iOS 26, changed how standard controls like tab bars, navigation bars and buttons look. Apps built with the iOS 26 SDK picked it up automatically, and Apple offered a temporary setting to keep the older look. Apple described that setting as temporary, so assume it won't be available forever, and make sure your screens look right with the new design.

Check your third-party libraries

Most apps depend on outside libraries for analytics, payments, crash reporting, maps and chat. When iOS changes, these libraries release updates, and old versions sometimes stop working or get flagged during App Store review.

Ask your developer for a list of libraries and their versions, and check which have iOS 27 updates. Libraries that haven't been updated in a year or more are a warning sign. They may need replacing, which is better done calmly now than in a rush before a deadline.

Apple also requires privacy manifests from apps and certain commonly used third-party SDKs, describing what data they collect and why. If your app was built a while ago, make sure every library you use includes one. Missing manifests can hold up review.

When the update becomes mandatory

Based on Apple's recent pattern, the rule change usually lands in late April. From that date, App Store Connect rejects uploads built with older SDKs. Your existing app stays in the store and keeps working for users. You just can't ship an update until you rebuild.

That's the trap. The day you urgently need to fix a bug or change a price, you discover the fix comes bundled with an SDK upgrade and a round of testing.

The same thing happens on Android every August, when Google raises its target API requirement. We explained that one in the Google Play Android 16 deadline. Both deadlines belong on your yearly maintenance calendar.

Should you use the new iOS 27 features?

Only where they help your customers. A few ideas that tend to be worth it for business apps:

• Siri and App Intents: letting users check an order or book a slot by voice is useful for repeat customers.

• Widgets: a delivery status, next appointment or account balance on the home screen brings people back without push notifications.

• Apple Intelligence writing tools: these work automatically in standard text fields, which is a reason to use standard components where you can.

New features are a product decision, not a maintenance task. Scope them separately, and don't let them delay the compatibility work.

A sensible order is: compatibility fixes first, shipped as a small update, then new features in a later release once you've seen how customers use the app on iOS 27. Two small, well-tested releases are safer than one large one.

Questions about iOS 27 and app updates

Will my app stop working on iOS 27?

Most apps keep working. Problems usually show up in specific areas like permissions, background tasks, or layouts that relied on older design behaviour. Testing your main flows on iOS 27 tells you quickly.

When do I have to build my app with the iOS 27 SDK?

Apple announces the date, and in recent years it has been late April. From that date, updates must be built with the new SDK. Your existing app stays available in the meantime.

How much does an iOS update cost?

For a well-maintained app, testing and small fixes can take a few days. Apps that are several versions behind, or use outdated libraries, can take a few weeks. A short code review gives you a real estimate.

Do I need to update my Android app too?

Yes, on its own schedule. Google requires apps to target Android 16 for updates from 31 August 2026. Plan both platforms together as part of your app maintenance.

Get your app checked

If you're not sure how your app will handle iOS 27 or next spring's SDK deadline, send us the App Store link. Our web and app development team will test the key flows and give you a fixed price for anything that needs fixing.