Running Optimizely CMS 12 on .NET 10 in Azure

Microsoft launched .NET 10 on 11 November 2025, and today .NET 10 (final) is available to select as the runtime for an Azure Web App.

To upgrade, follow these steps.

1. Install the SDK

Download the .NET 10 SDK, or optionally, Visual Studio 2026.

2. Update your project file(s)

Set the target framework to .NET 10.

<Project Sdk="Microsoft.NET.Sdk.Web">
  <PropertyGroup>
    <TargetFramework>net10.0</TargetFramework>
  </PropertyGroup>
</Project>

3. Update your CI/CD pipeline

I use Azure DevOps, and added the following step to my build pipeline:

- task: UseDotNet@2
  displayName: 'use dotnet 10.0'
  inputs:
    packageType: 'sdk'
    version: '10.0.x'

4. Update your Azure Web App Runtime

Choose the .NET 10 runtime.

5. Deploy your updated website

Deploy your updated website to the updated Web App, and optionally display your stack details in the footer, like I do! 😎