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Upgrading any .NET

Nuguid, Andrei 0 Reputation points
2026-04-24T13:05:46.24+00:00

I am currently working with .NET vulnerabilities especially the SEoL versions. Unfortunately, the version like less 8/9/10 doesn't update if I tried to install the latest version.

How do I update these old versions to latest?

Developer technologies | .NET | Other
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  1. Lizzy Dinh (WICLOUD CORPORATION) 440 Reputation points Microsoft External Staff Moderator
    2026-04-27T06:33:06.7766667+00:00

    Hi @Nuguid, Andrei ,

    Thank you for reaching out and sharing your concern with us—I truly appreciate you bringing this up.

    To clarify, installing a newer version of the .NET runtime does not automatically upgrade your existing applications. .NET is designed to support side-by-side installations, meaning multiple versions can coexist on the same machine without affecting one another. As a result, applications will continue to run based on the specific runtime version they were originally targeting.

    To take advantage of a newer .NET version, you’ll need to explicitly update your application’s target framework. Since you’ve already installed the latest SDK/runtime, you can update your project file as follows:

    <TargetFramework>[The latest .NET version]</TargetFramework>

    After making this change, please rebuild and redeploy your application to apply the update.

    If you’d like additional assistance, Visual Studio Copilot’s modernization agent can be a helpful tool. It can analyze your project, suggest an upgrade plan, and even automatically address certain issues during the process.

    I hope this helps clarify things and supports your next steps. If you have any further questions or need additional guidance, please don’t hesitate to reach out—I’m here to help.

    If you have a moment, I would also really appreciate your feedback on the support provided.

    Wishing you a great day ahead!

  2. Bruce (SqlWork.com) 83,821 Reputation points
    2026-04-24T14:31:27.1766667+00:00

    Unlike classic .net, .net core versions are installed side by side. So if you install versions 8, 9 and 10, you must update each separately (the updates are also installed side by side). a .net core application will only run with the runtime version it was built with. While standard windows update should handle the updates, you can manually install:

    https://dotnet.microsoft.com/en-us/download/dotnet

    if using a scanner, you may need to delete previous patch versions via the uninstall tool.

    https://learn.microsoft.com/en-us/dotnet/core/install/remove-runtime-sdk-versions?pivots=os-windows

    in November both versions 8 & 9 will be out of support. Before then all .netcore applications will need to be rebuilt with .net10+. Then you may need to delete the unsupported runtimes to stop the scanner errors.

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  3. Q&A Assist
    2026-04-24T13:05:58.73+00:00
    AI generated content. This question contains an answer created with AI from Q&A Assist. Learn more

    Updating to the latest .NET involves two separate steps: updating the environment (SDK/runtime on the machine) and updating each application’s target framework.

    1. Install the latest .NET SDK/runtime
      • Install the newest supported .NET SDK on the machine. The SDK includes the updated runtime, CLI, and build system.
      • Use one of these methods:
        • Download the latest SDK from the .NET website installers/archives for the OS and architecture in use.
        • Or use the OS package manager:
          • macOS: Homebrew cask for dotnet-sdk.
          • Linux: Follow the Linux install instructions.
          • Windows: Use winget packages for Microsoft .NET SDK.
      • On Visual Studio machines, installing a newer Visual Studio version will also install newer .NET SDKs automatically.
    2. Upgrade each application’s target framework
      • For each .NET app, edit the project file (*.csproj, *.vbproj, or *.fsproj).
      • Change the TargetFramework (or TargetFrameworks) to the newer version, for example: 
             <TargetFramework>net8.0</TargetFramework>
      • Save the file and rebuild the project using the new SDK.
      • If additional code changes are required (for example, due to breaking changes or removed APIs), the build will emit warnings and errors that indicate what must be fixed.
      • If workloads (like MAUI, Android, iOS) are used, run dotnet workload restore after installing the new SDK so workloads are restored for the new version.
    3. Keep .NET 8 updated with servicing releases
      • Once on .NET 8, use Windows Update/WSUS/MU Catalog to receive .NET 8 servicing updates (for example, 8.0.14, 8.0.17, 8.0.20, 8.0.21). These updates are in-place upgrades that replace the previous 8.0 patch level.
      • Ensure the OS version is supported for .NET 8 so these updates are offered.

    By installing the latest SDK and retargeting projects, older SEoL versions (for example, older .NET Core/.NET versions) can be moved to a supported, patched .NET release.

    References:

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