How to Update .NET Core: Step-by-Step Migration Guide

I remember updating .NET Core on a legacy server back in Pittsburgh scrap yards. The process has gotten much cleaner since then, but still trips up even experienced devs.

This migration path works for any project, from small utilities to enterprise apps. You’ll need the latest SDK installed and a backup of your solution. The CLI handles most of the heavy lifting.

Verifying the update takes one command. I’ve seen teams waste hours missing this step, only to debug version mismatches later. The output tells you exactly what changed.

Works across Windows, macOS, and Linux. The same commands apply everywhere, with zero config differences between operating systems.

What Youll Need

Instructions

Here’s the process I follow for seamless updates across projects and environments.

Open a terminal or command prompt and run dotnet –list-sdks to see installed versions. This shows all SDKs on your system, with the newest at the top. Note the version you want to update from—it’s critical for migration planning.

Also run dotnet –list-runtimes to check runtime versions. Mismatched SDK and runtime versions often cause compatibility issues. If you see multiple versions, decide whether to update or uninstall the old ones.

Visit the official .NET downloads page and grab the latest SDK for your operating system. I always choose the x64 version unless working with ARM-based systems. The installer handles most dependencies automatically, but ensure you have admin rights.

Run the installer and follow the prompts. When complete, reopen your terminal and run dotnet –info to confirm the new SDK appears. If it doesn’t, restart your machine—sometimes PATH updates need a reboot.

Navigate to your project directory and open the .csproj file. Locate the <TargetFramework> or <TargetFrameworks> tag and update it to the new version, such as net8.0. Save the file and restore packages with dotnet restore.

Watch for compatibility warnings during restore. If you see errors about missing packages, check NuGet for updated versions. Some libraries need manual updates to support newer .NET versions.

Build the project with dotnet build and address any errors. Common issues include deprecated APIs or removed namespaces. The compiler will flag these clearly, often with suggestions for alternatives.

Run your application and test critical workflows. Pay special attention to serialization, reflection, and async code—these areas often behave differently between versions. Use dotnet test to verify unit tests pass.

Once the new version is stable, uninstall old SDKs via your system’s add/remove programs. Keeping multiple versions can clutter your environment and cause confusion. I recommend retaining only the latest stable and LTS versions.

Run dotnet –list-sdks again to confirm removal. If you encounter issues, re-install the latest SDK—it’s self-contained and won’t interfere with other applications.

Tips and Common Mistakes

These insights will help you avoid the most common pitfalls when updating your environment.

Verification Shortcut: In Step 1, I always pipe the output of dotnet –list-sdks to a text file for easier comparison between versions. This saves time when you’re planning which versions to keep or remove during the cleanup phase.

Installation Pro Tip: For Step 2, if you’re working on Windows, run the installer as administrator even if your account has admin rights. I’ve seen cases where the PATH variables don’t update correctly without explicit elevation, which causes the new SDK to not appear in dotnet –info.

Project File Strategy: During Step 3, before updating the <TargetFramework> tag, I recommend creating a backup of your .csproj file. Some projects have conditional logic based on framework versions that might not be immediately obvious.

Testing Focus Areas: In Step 4, the areas I mentioned—serialization, reflection, and async code—are particularly vulnerable between versions. I once spent hours debugging a serialization issue that turned out to be a breaking change in how JSON handled null values.

Frequently Asked Questions

Updating .NET Core ensures your applications stay secure, performant, and feature-rich. With the right tools and steps, the migration process can be smooth and hassle-free. 🎯 Now that you’re equipped with the know-how, take the next step and test your updated project in a staging environment to catch any issues early!