Azure Functions: Upgrade your app to newer version as .NET 8 Isolated will reach EOL on 10.11.2026 and will no longer be supported.

Hi @Kim Strasser

Thank you for reaching out to Microsoft Q&A.

The warnings you are seeing in your Azure Functions project are informational lifecycle warnings and not actual errors. These warnings indicate that the currently used runtime versions (.NET 8 Isolated, .NET 8 In-process, and PowerShell 7.4) will reach end of support on November 10, 2026. At present, Azure Functions Runtime v4 only supports up to these versions, so there is no higher version available today that you can upgrade to in order to remove these warnings. Additionally, the in-process execution model itself is being retired after this date, which makes migration mandatory for long-term support. Therefore, these warnings are expected behavior and are meant to help you plan future upgrades rather than indicating a current issue with your application.

https://learn.microsoft.com/en-us/azure/azure-functions/dotnet-isolated-process-guide?

https://learn.microsoft.com/en-us/azure/azure-functions/functions-versions?

Refer below points to resolve this issue or this is the workaround

Understand that these warnings are expected and require no immediate fix

• Azure Functions v4 currently supports only .NET 8 and PowerShell 7.4
• These versions are still fully supported today
• The warning is only advisory to plan upgrades before November 10, 2026

Migrate from .NET In-process to .NET Isolated model (Important action)

• The in-process model will be retired on November 10, 2026
• To ensure future compatibility, migrate your app to isolated worker model
• Update your project file:

<!-- Remove -->
<PackageReference Include="Microsoft.NET.Sdk.Functions" />
<!-- Add -->
<PackageReference Include="Microsoft.Azure.Functions.Worker" />
<PackageReference Include="Microsoft.Azure.Functions.Worker.Sdk" />

• Create a Program.cs as entry point and adjust function signatures accordingly

Plan upgrade for .NET version in future (No immediate change required)

• Continue using .NET 8 isolated for now
• Before November 2026, upgrade to a newer supported version (e.g., .NET 9 or .NET 10 when available)
• Example future update:

<TargetFramework>net9.0</TargetFramework>

PowerShell 7.4 warning does not require immediate action

• It is the latest supported version available today
• Upgrade only when Azure Functions supports a newer PowerShell version

Ensure your Function App is running on Runtime version v4 and using the recommended Isolated worker model for futureproofing.
Plan a lifecycle upgrade strategy to periodically update runtime versions before their official end-of-support dates to avoid service disruption.

I don´t use "Microsoft.NET.Sdk.Functions" in my project.

Should I only change net8.0 to net9.0?

<Project Sdk="Microsoft.NET.Sdk">
	<PropertyGroup>
		<TargetFramework>net8.0</TargetFramework>
		<AzureFunctionsVersion>v4</AzureFunctionsVersion>
		<OutputType>Exe</OutputType>
		<ImplicitUsings>enable</ImplicitUsings>
		<Nullable>annotations</Nullable>
		<FunctionsWorkerToolPath>$(MSBuildProjectDirectory)\obj\Debug\net8.0\WorkerExtensions\bin\Release\net8.0</FunctionsWorkerToolPath>

	</PropertyGroup>
	<ItemGroup>
		<FrameworkReference Include="Microsoft.AspNetCore.App" />
		<PackageReference Include="Azure.Identity" Version="1.21.0" />
		<PackageReference Include="Microsoft.ApplicationInsights.WorkerService" Version="3.1.2" />
		<PackageReference Include="Microsoft.Azure.Functions.Worker" Version="2.52.0" />
		<PackageReference Include="Microsoft.Azure.Functions.Worker.ApplicationInsights" Version="2.50.0" />
		<PackageReference Include="Microsoft.Azure.Functions.Worker.Extensions.Http.AspNetCore" Version="2.1.0" />
		<PackageReference Include="Microsoft.Azure.Functions.Worker.Sdk" Version="2.0.7" OutputItemType="Analyzer" />
		<PackageReference Include="OpenTelemetry.Api" Version="1.15.3" />
		<PackageReference Include="PlayFabAllSDK" Version="1.225.260526" />
	</ItemGroup>
	<ItemGroup>
		<Compile Update="Properties\Resources.Designer.cs">
			<DesignTime>True</DesignTime>
			<AutoGen>True</AutoGen>
			<DependentUpon>Resources.resx</DependentUpon>
		</Compile>
	</ItemGroup>
	<ItemGroup>
		<EmbeddedResource Update="Properties\Resources.resx">
			<Generator>ResXFileCodeGenerator</Generator>
			<LastGenOutput>Resources.Designer.cs</LastGenOutput>
		</EmbeddedResource>
	</ItemGroup>
	<ItemGroup>
		<None Update="host.json">
			<CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
		</None>
		<None Update="local.settings.json">
			<CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
			<CopyToPublishDirectory>Never</CopyToPublishDirectory>
		</None>
	</ItemGroup>
</Project>

Upgrading your Azure Functions application from .NET 8 to .NET 9 is a valid approach for long-term support since .NET 8 will reach end of support in November 2026. However, this upgrade is not just a simple change in the <TargetFramework> value. Even though the isolated worker model (which your app is already using) allows targeting newer .NET versions, successful migration depends on ensuring that Azure Functions runtime, hosting plan, tooling, and dependencies all support .NET 9. If these prerequisites are not aligned, the application may deploy but fail at runtime (e.g., functions not appearing, host startup failures). Therefore, the upgrade must be done carefully with both project and Azure configuration updates.

Refer below points to resolve this issue or this is the workaround

Update Target Framework and Worker Tool Path in project

• Modify your .csproj file:

<TargetFramework>net9.0</TargetFramework>

• Also update the Functions worker path accordingly:

<FunctionsWorkerToolPath>
$(MSBuildProjectDirectory)\obj\Debug\net9.0\WorkerExtensions\bin\Release\net9.0
</FunctionsWorkerToolPath>

Install .NET 9 SDK and update Azure Functions tooling

• Install .NET 9 SDK locally and verify:

dotnet --list-sdks

• Update:
  • Azure Functions Core Tools
    • Visual Studio / VS Code extensions
    • Ensure tooling recognizes .NET 9, otherwise build/deploy issues may occur

Upgrade all Azure Functions packages to latest compatible versions

• Check outdated packages:

dotnet list package --outdated

• Upgrade core packages:

dotnet add package Microsoft.Azure.Functions.Worker
dotnet add package Microsoft.Azure.Functions.Worker.Sdk

• Also update extensions (HTTP, Storage, etc.) to latest versions

Update Azure Function App configuration in Portal or CLI

• Ensure:
  • FUNCTIONS_WORKER_RUNTIME = dotnet-isolated
  • Set runtime version:
    • Windows: netFrameworkVersion = v9.0
      • Linux: linuxFxVersion = DOTNET-ISOLATED|9.0
      • Verify your hosting plan supports .NET 9 (Premium/Dedicated preferred if unsure)

Test and validate before production deployment

• Run locally:

func start

• Deploy to staging slot and verify:
• Functions are visible in Azure Portal
  • Triggers execute successfully
  • No startup/runtime errors