Our app still supports iOS12, and still in the App Delegate, and we are expected to migrate and update our minimum iOS version to iOS15.
What APIs should we review in the docs related to lifecycles, device and screen bounds, what expected breaking in UI as we are using custom navigation toolbars, and custom tab bars.
Hi there!
What APIs should we review in the docs related to lifecycles, device and screen bounds,
If you haven't seen it already, I'd start by checking out these videos as they give you a good overview of the mindset to have when approaching this topic. We see scene adoption as a necessary part of being able to prepare to support any available size at runtime:
"Modernize your UIKit app" https://developer.apple.com/videos/play/wwdc2026/278/
Very similar vibe on this one, with more iPhone Duo specific details:
"Prepare your app for iPhone Duo" https://developer.apple.com/videos/play/tech-talks/111461/
For detailed help on what to do, take a look at the transition guide:
https://developer.apple.com/documentation/UIKit/transitioning-to-the-uikit-scene-based-life-cycle
That will give you a lot of details of what to look for and change out when migrating to the scene-based life cycle.
The last thing I'd recommend you do is check out the App Resizability skill in Xcode 27.1:
https://developer.apple.com/videos/play/tech-talks/111461/?time=559
This skill go through your code and help you migrate to best practices for resizing. It will even help you adopt UIScene life cycle. Check it out!
what expected breaking in UI as we are using custom navigation toolbars, and custom tab bars.
For this, you'll just have to try and see.
