Steps to reproduce

Make sure you're using Xcode 16.3
Create a new flutter app
Run the app on a physical device (Tested on iPhone 16 Pro Max and iPad M1 Air. Requires iOS 18.4.1+)
When Xcode opens, check the logs

Expected results

I wouldn't expect the log to appear in the console or at least, I hadn't noticed it prior to Xcode 16.3

Actual results

The log below appears in Xcode.

CLIENT OF UIKIT REQUIRES UPDATE: This process does not adopt UIScene lifecycle. This will become an assert in a future version.
FlutterView implements focusItemsInRect: - caching for linear focus movement is limited as long as this view is on screen.
flutter: The Dart VM service is listening on http://127.0.0.1:53211/xwswRNYlr8A=/
App is being debugged, do not track this hang
Hang detected: 0.40s (debugger attached, not reporting)
App is being debugged, do not track this hang
Hang detected: 0.42s (debugger attached, not reporting)
Message from debugger: killed

Code sample

The counter app should suffice for this.

Screenshots or Video

No response

Logs

I found this discussion related to it in the apple forums https://developer.apple.com/forums/thread/778016

CLIENT OF UIKIT REQUIRES UPDATE: This process does not adopt UIScene lifecycle. This will become an assert in a future version.
FlutterView implements focusItemsInRect: - caching for linear focus movement is limited as long as this view is on screen.
flutter: The Dart VM service is listening on http://127.0.0.1:53211/xwswRNYlr8A=/
App is being debugged, do not track this hang
Hang detected: 0.40s (debugger attached, not reporting)
App is being debugged, do not track this hang
Hang detected: 0.42s (debugger attached, not reporting)

I tested a UIKit and SwiftUI example and didn't see similar logs. Perhaps the sample I used had an effect but I'm not certain. The UIKit sample is pasted below. The Hang detected message also appears in the native iOS sample apps.

UIKit sample

import UIKit
class ViewController: UIViewController {
    override func viewDidLoad() {
        super.viewDidLoad()
        setupUI()
    }
    func setupUI() {
        // Create a label
        let label = UILabel()
        label.text = "Hello, World!"
        label.textAlignment = .center
        label.translatesAutoresizingMaskIntoConstraints = false // Enable Auto Layout
        // Add the label to the view
        view.addSubview(label)
        // Center the label horizontally and vertically
        NSLayoutConstraint.activate([
            label.centerXAnchor.constraint(equalTo: view.centerXAnchor),
            label.centerYAnchor.constraint(equalTo: view.centerYAnchor)
        ])
    }
}

Flutter Doctor output

Doctor output

[✓] Flutter (Channel stable, 3.29.3, on macOS 15.4 24E248 darwin-arm64, locale en-US) [6.0s]
    • Flutter version 3.29.3 on channel stable at /Users/deanli/dev/stable
    • Upstream repository https://github.com/flutter/flutter.git
    • Framework revision ea121f8859 (5 days ago), 2025-04-11 19:10:07 +0000
    • Engine revision cf56914b32
    • Dart version 3.7.2
    • DevTools version 2.42.3
[✓] Android toolchain - develop for Android devices (Android SDK version 36.0.0) [7.2s]
    • Android SDK at /Users/deanli/Library/Android/sdk
    • Platform android-36, build-tools 36.0.0
    • Java binary at: /Users/deanli/Applications/Android Studio Meerkat Feature Drop 2024.3.2 RC 2.app/Contents/jbr/Contents/Home/bin/java
      This JDK is specified in your Flutter configuration.
      To change the current JDK, run: `flutter config --jdk-dir="path/to/jdk"`.
    • Java version OpenJDK Runtime Environment (build 21.0.6+-13119726-b895.91)
    • All Android licenses accepted.
[✓] Xcode - develop for iOS and macOS (Xcode 16.3) [6.6s]
    • Xcode at /Applications/Xcode-16.3.0.app/Contents/Developer
    • Build 16E140
    • CocoaPods version 1.16.2
[✓] Chrome - develop for the web [23ms]
    • Chrome at /Applications/Google Chrome.app/Contents/MacOS/Google Chrome
[✓] Android Studio (version 2024.3) [22ms]
    • Android Studio at /Users/deanli/Applications/Android Studio Meerkat Feature Drop 2024.3.2 RC 2.app/Contents
    • Flutter plugin can be installed from:
      🔨 https://plugins.jetbrains.com/plugin/9212-flutter
    • Dart plugin can be installed from:
      🔨 https://plugins.jetbrains.com/plugin/6351-dart
    • android-studio-dir = /Users/deanli/Applications/Android Studio Meerkat Feature Drop 2024.3.2 RC 2.app
    • Java version OpenJDK Runtime Environment (build 21.0.6+-13119726-b895.91)
[✓] Android Studio (version 2024.2) [19ms]
    • Android Studio at /Users/deanli/Applications/Android Studio.app/Contents
    • Flutter plugin can be installed from:
      🔨 https://plugins.jetbrains.com/plugin/9212-flutter
    • Dart plugin can be installed from:
      🔨 https://plugins.jetbrains.com/plugin/6351-dart
    • Java version OpenJDK Runtime Environment (build 21.0.5+-12932927-b750.29)
[✓] VS Code (version 1.98.2) [19ms]
    • VS Code at /Applications/Visual Studio Code.app/Contents
    • Flutter extension version 3.108.0
[✓] Connected device (5 available) [7.8s]
    • Dean’s iPad (wireless) (mobile) • 00008103-000825C811E3401E • ios            • iOS 18.4 22E240
    • Nexus (wireless) (mobile)       • 00008020-001875E83A38002E • ios            • iOS 18.4 22E240
    • macOS (desktop)                 • macos                     • darwin-arm64   • macOS 15.4 24E248 darwin-arm64
    • Mac Designed for iPad (desktop) • mac-designed-for-ipad     • darwin         • macOS 15.4 24E248 darwin-arm64
    • Chrome (web)                    • chrome                    • web-javascript • Google Chrome 135.0.7049.85
    ! Error: Browsing on the local area network for iPhone. Ensure the device is unlocked and attached with a cable or associated with the same local area network as this Mac.
      The device must be opted into Developer Mode to connect wirelessly. (code -27)
    ! Error: Browsing on the local area network for iPhone 16 Pro Max. Ensure the device is unlocked and attached with a cable or associated with the same local area network as this Mac.
      The device must be opted into Developer Mode to connect wirelessly. (code -27)
[✓] Network resources [1,531ms]
    • All expected network resources are available.
• No issues found!

[!] Flutter (Channel master, 3.32.0-1.0.pre.101, on macOS 15.4 24E248 darwin-arm64, locale en-US) [3.2s]
    • Flutter version 3.32.0-1.0.pre.101 on channel master at /Users/deanli/dev/master
    ! Warning: `flutter` on your path resolves to /Users/deanli/dev/stable/bin/flutter, which is not inside your current Flutter SDK checkout at /Users/deanli/dev/master. Consider adding /Users/deanli/dev/master/bin to the front of your path.
    ! Warning: `dart` on your path resolves to /Users/deanli/dev/stable/bin/dart, which is not inside your current Flutter SDK checkout at /Users/deanli/dev/master. Consider adding /Users/deanli/dev/master/bin to the front of your path.
    • Upstream repository https://github.com/flutter/flutter.git
    • Framework revision 10a1d1520e (7 hours ago), 2025-04-15 20:29:36 -0700
    • Engine revision 10a1d1520e
    • Dart version 3.8.0 (build 3.8.0-265.0.dev)
    • DevTools version 2.45.0-dev.0
    • If those were intentional, you can disregard the above warnings; however it is recommended to use "git" directly to perform update checks and upgrades.
[✓] Android toolchain - develop for Android devices (Android SDK version 36.0.0) [3.0s]
    • Android SDK at /Users/deanli/Library/Android/sdk
    • Platform android-36, build-tools 36.0.0
    • Java binary at: /Users/deanli/Applications/Android Studio Meerkat Feature Drop 2024.3.2 RC 2.app/Contents/jbr/Contents/Home/bin/java
      This JDK is specified in your Flutter configuration.
      To change the current JDK, run: `flutter config --jdk-dir="path/to/jdk"`.
    • Java version OpenJDK Runtime Environment (build 21.0.6+-13119726-b895.91)
    • All Android licenses accepted.
[✓] Xcode - develop for iOS and macOS (Xcode 16.3) [1,878ms]
    • Xcode at /Applications/Xcode-16.3.0.app/Contents/Developer
    • Build 16E140
    • CocoaPods version 1.16.2
[✓] Chrome - develop for the web [15ms]
    • Chrome at /Applications/Google Chrome.app/Contents/MacOS/Google Chrome
[✓] Android Studio (version 2024.3) [14ms]
    • Android Studio at /Users/deanli/Applications/Android Studio Meerkat Feature Drop 2024.3.2 RC 2.app/Contents
    • Flutter plugin can be installed from:
      🔨 https://plugins.jetbrains.com/plugin/9212-flutter
    • Dart plugin can be installed from:
      🔨 https://plugins.jetbrains.com/plugin/6351-dart
    • android-studio-dir = /Users/deanli/Applications/Android Studio Meerkat Feature Drop 2024.3.2 RC 2.app
    • Java version OpenJDK Runtime Environment (build 21.0.6+-13119726-b895.91)
[✓] Android Studio (version 2024.2) [12ms]
    • Android Studio at /Users/deanli/Applications/Android Studio.app/Contents
    • Flutter plugin can be installed from:
      🔨 https://plugins.jetbrains.com/plugin/9212-flutter
    • Dart plugin can be installed from:
      🔨 https://plugins.jetbrains.com/plugin/6351-dart
    • Java version OpenJDK Runtime Environment (build 21.0.5+-12932927-b750.29)
[✓] VS Code (version 1.98.2) [12ms]
    • VS Code at /Applications/Visual Studio Code.app/Contents
    • Flutter extension version 3.108.0
[✓] Connected device (5 available) [8.2s]
    • Dean’s iPad (wireless) (mobile)       • 00008103-000825C811E3401E • ios            • iOS 18.4 22E240
    • iPhone 16 Pro Max (wireless) (mobile) • 00008140-00194CC23A68801C • ios            • iOS 18.4 22E240
    • Nexus (wireless) (mobile)             • 00008020-001875E83A38002E • ios            • iOS 18.4 22E240
    • macOS (desktop)                       • macos                     • darwin-arm64   • macOS 15.4 24E248 darwin-arm64
    • Chrome (web)                          • chrome                    • web-javascript • Google Chrome 135.0.7049.85
    ! Error: Browsing on the local area network for iPhone. Ensure the device is unlocked and attached with a cable or associated with the same local area network as this Mac.
      The device must be opted into Developer Mode to connect wirelessly. (code -27)
[✓] Network resources [676ms]
    • All expected network resources are available.
! Doctor found issues in 1 category.