PersistentState Attribute not working on iPhone 16.5

[brackers17]

Is there an existing issue for this?

• I have searched the existing issues

Describe the bug

When using the [PersistentState] attribute on an iPhone or iPad running iOS 16.5, we are seeing unexpected behavior when the app is backgrounded.

Expected Behavior

The app should reconnect and restore state, with the counter still set to the previous value.

Notes

• On iOS 18.6.2, the expected behavior is observed.
• Upgrading the device that experienced the issue resolved the problem.

Steps To Reproduce

1. Scaffold a new .NET 10 project with Blazor Web App and the following settings:

• .NET 10 Preview
• Auth: none
• Interactive render mode: server
• Interactivity: global
• include sample pages: true

2. On the counter page add the [PersistentState] above the current count and change it to a property.
3. In Program.cs add DisconnectedCircuitMaxRetained = 0 inside the AddInteractiveServerComponents method

.AddInteractiveServerComponents(options => { options.DisconnectedCircuitMaxRetained = 0; });

4. Deploy to IIS and go to an iPhone/iPad
5. Increase the counter and leave the Safari browser for 30 seconds

Exceptions (if any)

No exceptions

.NET Version

10.0.100-preview.7.25380.108

Anything else?

VS: 17.14.12 Preview 1.0

.NET SDK:
Version: 10.0.100-preview.7.25380.108
Commit: 30000d883e
Workload version: 10.0.100-manifests.8bb6be96
MSBuild version: 17.15.0-preview-25380-108+30000d883

Runtime Environment:
OS Name: Windows
OS Version: 10.0.26100
OS Platform: Windows
RID: win-x64
Base Path: C:\Program Files\dotnet\sdk\10.0.100-preview.7.25380.108\

.NET workloads installed:
[maui-windows]
Installation Source: VS 17.14.36408.4
Manifest Version: 10.0.0-preview.6.25359.8/10.0.100-preview.6
Manifest Path: C:\Program Files\dotnet\sdk-manifests\10.0.100-preview.6\microsoft.net.sdk.maui\10.0.0-preview.6.25359.8\WorkloadManifest.json
Install Type: Msi

[maccatalyst]
Installation Source: VS 17.14.36408.4
Manifest Version: 18.5.10415-net10-p6/10.0.100-preview.6
Manifest Path: C:\Program Files\dotnet\sdk-manifests\10.0.100-preview.6\microsoft.net.sdk.maccatalyst\18.5.10415-net10-p6\WorkloadManifest.json
Install Type: Msi

[ios]
Installation Source: VS 17.14.36408.4
Manifest Version: 18.5.10415-net10-p6/10.0.100-preview.6
Manifest Path: C:\Program Files\dotnet\sdk-manifests\10.0.100-preview.6\microsoft.net.sdk.ios\18.5.10415-net10-p6\WorkloadManifest.json
Install Type: Msi

[android]
Installation Source: VS 17.14.36408.4
Manifest Version: 36.0.0-preview.6.169/10.0.100-preview.6
Manifest Path: C:\Program Files\dotnet\sdk-manifests\10.0.100-preview.6\microsoft.net.sdk.android\36.0.0-preview.6.169\WorkloadManifest.json
Install Type: Msi

Configured to use workload sets when installing new manifests.
Workloads are configured to install and update using workload versions, but none were found. Run "dotnet workload restore" to install a workload version.

Host:
Version: 10.0.0-preview.7.25380.108
Architecture: x64
Commit: 30000d883e

.NET SDKs installed:
3.1.426 [C:\Program Files\dotnet\sdk]
6.0.428 [C:\Program Files\dotnet\sdk]
9.0.304 [C:\Program Files\dotnet\sdk]
10.0.100-preview.7.25380.108 [C:\Program Files\dotnet\sdk]

.NET runtimes installed:
Microsoft.AspNetCore.App 3.1.32 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 6.0.36 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 8.0.19 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 9.0.8 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 10.0.0-preview.7.25380.108 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.NETCore.App 3.1.32 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 6.0.36 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 8.0.19 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 9.0.8 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 10.0.0-preview.7.25380.108 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.WindowsDesktop.App 3.1.32 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
Microsoft.WindowsDesktop.App 6.0.36 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
Microsoft.WindowsDesktop.App 8.0.19 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
Microsoft.WindowsDesktop.App 9.0.8 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
Microsoft.WindowsDesktop.App 10.0.0-preview.7.25380.108 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]

Other architectures found:
x86 [C:\Program Files (x86)\dotnet]
registered at [HKLM\SOFTWARE\dotnet\Setup\InstalledVersions\x86\InstallLocation]

Environment variables:
Not set

global.json file:
Not found

[javiercn]

@brackers17 thanks for contacting us.

It likely has to do with us using some JS API that Safari 16 might not support.

Likely something like https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Promise/withResolvers

As per our support policy https://learn.microsoft.com/en-us/aspnet/core/blazor/supported-platforms?view=aspnetcore-9.0 iOS 16 is not part of our support matrix. So, we don't plan to take action on this.

In most cases, you can use a polyfill if you need to support older browser versions at your own risk.