Introduction
Ubuntu 26.04 (Resolute Raccoon) has officially arrived, and with it comes a new wave of opportunities for .NET developers. Canonical and Microsoft have collaborated to ensure seamless integration, making this LTS release a solid foundation for building and running .NET applications. From the default inclusion of .NET 10 to advanced security features and container optimizations, there’s plenty to explore. In this article, we’ll break down the eight most important updates you need to know—each with actionable insights to help you get started quickly. Whether you’re upgrading from a previous release or jumping in fresh, these changes will streamline your development workflow.
1. Ubuntu 26.04 Ships with .NET 10 as the Default LTS
Every new Ubuntu LTS brings the latest .NET LTS version, and Resolute Raccoon is no exception. .NET 10 is now the standard runtime and SDK available directly from Ubuntu’s repositories. This means you can develop, deploy, and run modern .NET applications without any extra configuration—just sudo apt install dotnet-sdk-10.0. The collaboration between Canonical and Microsoft ensures that .NET is a fully supported toolchain on Ubuntu, with rigorous validation from both teams. For developers, this translates to a stable, high-performance environment that’s ready for production workloads from day one. If you’re starting a new project or migrating an existing one, .NET 10 on Ubuntu 26.04 offers the best compatibility and performance out of the box.
2. Installing .NET 10: A Simple One-Liner
Getting started with .NET 10 on Ubuntu 26.04 is as easy as running two commands. First, update your package list with sudo apt update, then install the SDK: sudo apt install dotnet-sdk-10.0. That’s it—the package is maintained by Canonical and kept up to date with security patches. The SDK includes everything you need: the runtime, libraries, and tools like dotnet build and dotnet run. This streamlined installation process is a direct result of the ongoing partnership between Microsoft and the Ubuntu team, ensuring that .NET feels like a first-class citizen. For a quick test, launch a terminal and run dotnet --version to verify the installation—you should see something like 10.0.105. No additional PPAs or manual downloads are required for the LTS version.
3. Access .NET 8 and 9 Through a Separate PPA
While .NET 10 is the flagship LTS on Ubuntu 26.04, you may still need older versions for legacy applications or specific compatibility requirements. Canonical provides a dedicated PPA (Personal Package Archive) feed for .NET 8 and .NET 9. This allows you to install multiple SDKs side by side without conflict. For example, to add .NET 8, simply register the PPA and install: sudo add-apt-repository ppa:dotnet/backports followed by sudo apt install dotnet-sdk-8.0. This approach ensures that long-term support versions remain accessible while keeping the default OS image lean. It’s a practical solution for teams that need to maintain compatibility across different .NET generations, especially in enterprise environments where gradual migration is essential.
4. New Ubuntu 26.04 Container Images for .NET
Containerized deployments get a boost with Ubuntu 26.04 container images tagged resolute. These images are built for .NET 10 and above, and are available on Docker Hub and other registries. If you were using the noble (24.04) tag, simply update your Dockerfile references to resolute to leverage the new OS release. The same flavor options persist, including chiseled images for minimal footprint. Note that containers share the host kernel, so a 26.04 container running on a 24.04 host will still use a Linux 6.x kernel. This backward compatibility is intentional, allowing teams to adopt the new OS without immediate kernel upgrades. For a smooth transition, test your existing .NET container workloads with the resolute images in a staging environment first.
5. Post-Quantum Cryptography: Future-Proof Your Apps
Security-conscious developers will appreciate that .NET 10 introduces post-quantum cryptography (PQC) support. Ubuntu 26.04 includes early cryptographic algorithms designed to resist attacks from quantum computers. While still in early adoption, this addition helps future-proof applications that handle sensitive data. Microsoft has integrated PQC into .NET’s cryptographic libraries, so you can start experimenting with algorithms like Kyber and Dilithium in your .NET 10 projects. Ubuntu’s release notes also highlight post-quantum cryptography as a key change, and the .NET team will begin extensive testing once Ubuntu 26.04 VMs are available in their lab. For now, you can explore the new APIs via the System.Security.Cryptography namespace. This is a proactive step toward quantum-safe development.
6. Say Goodbye to cgroup v1: Full Transition to v2
Ubuntu 26.04 removes support for cgroup v1, fully embracing cgroup v2. This change is primarily relevant for containerized environments, as cgroup v2 is the modern standard for resource management in Linux. The good news: .NET added support for cgroup v2 years ago, so most applications will work without any modifications. However, if you rely on legacy container orchestration tools that assume v1, you may need to update your configurations. The .NET team has been running on cgroup v2 in their CI pipelines for some time, ensuring compatibility is a non-event for the majority of users. To verify your environment, check the contents of /sys/fs/cgroup—if you see only v2 hierarchies, you’re all set. This transition ultimately brings better isolation and performance to containerized .NET workloads.
7. The Testing Journey: How .NET Prepared for Ubuntu 26.04
Behind the scenes, the .NET team has been on a “road to Ubuntu 26.04” since early 2025. They began by testing Debian 13 and Ubuntu 24.10 in continuous integration, followed by direct testing of 26.04 in late 2025. Every pull request in the dotnet/runtime repository now runs validation on Ubuntu 26.04 container images. This extensive early adoption means that the .NET runtime is one of the most thoroughly tested workloads on Resolute Raccoon—even before the official release. While intermediate Ubuntu standard releases often require minor adjustments, the preparation pays off at GA time. For developers, this rigorous testing translates into fewer surprises during upgrades. If you encounter any issues, the .NET GitHub issue tracker is your best resource for reporting problems or finding workarounds.
8. Running C# in a Container: A Quick Demo
To see everything in action, let’s run a C# snippet inside an Ubuntu 26.04 container. Start a fresh container with docker run --rm -it ubuntu:resolute, update packages, and install the .NET SDK as described earlier. Then, execute a simple “Hello World” using a heredoc: dotnet run - << 'EOF' followed by your C# code. The output will confirm the OS description and .NET version. This pattern is popular among automation tools and AI agents—they often use stdin to run Python scripts, but C# works just as well. The example demonstrates how seamless .NET integration is on Ubuntu 26.04. It also highlights the versatility of the platform, whether you’re building microservices, console apps, or AI-powered tools. Try it yourself and see how fast and simple it is.
Conclusion
Ubuntu 26.04 (Resolute Raccoon) brings a host of improvements for the .NET ecosystem, from the default LTS version to advanced cryptography and container updates. Whether you’re installing via apt, running containers, or adopting post-quantum security, the collaboration between Canonical and Microsoft ensures a smooth experience. The removal of cgroup v1 and the ongoing testing efforts underscore a commitment to modern, reliable infrastructure. Now is the perfect time to upgrade your development environment and take advantage of these enhancements. For detailed installation steps and further resources, refer to the official Ubuntu documentation and the .NET GitHub repository.