.NETPro #31: .NET 11 Preview 3 is Here: Finally Better Async Debugging + Signed Containers
🌍 Your guide to the latest runtime improvements, AI security, and legacy app modernization
You know that moment when you’re deep in a complex async codebase at 2 a.m., praying the stack trace actually makes sense? Or when you push a container to production and quietly hope no one tampers with it?
I’ve been there too many times. That’s why .NET 11 Preview 3 feels like a breath of fresh air. With its polished runtime async improvements and officially signed container images, it’s solving real headaches.
In this issue, we explore these highlights along with .NET MAUI pin clustering, free monitoring using Uptime Kuma, safe AI agents in Docker sandboxes, and other key April 2026 updates, plus expert insights you won’t want to miss.
Take a look at today’s highlights first:
➡️ April 2026 .NET updates bring important security and reliability fixes
➡️ ASP.NET Core 2.3 officially reaches end of support next year
➡️ Scale mobile growth beyond ads—with full revenue visibility
➡️ .NET MAUI Maps introduces powerful pin clustering support in .NET 11 Preview 3
➡️ Understand why assessments drive successful .NET and Java modernization efforts
➡️ Run AI agents safely using Docker sandboxed microVM environments
Keep reading, and when you’re done, drop us a note about what you enjoyed and how we can make the next edition more helpful.
Cheers!
Adrija Mitra
Editor-in-Chief
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📰 .NET 11 Preview 3
What’s actually worth testing right now!
The .NET team shipped Preview 3 on April 14, 2026, and this one feels more mature than typical previews. With GA scheduled for November, it’s a smart moment to start testing, especially if you ship cloud-native or async-heavy services. You can safely target net10.0 today and upgrade later with minimal friction.
The features that impressed me most in this release:
➡️ Runtime Async is now far more usable: The preview gate
(<EnablePreviewFeatures>)is gone for net11.0 projects. Just set<Features>runtime-async=on</Features>and you get genuinely cleaner live stack traces, lower allocation overhead, and dramatically better debugging. This is a game-changer for anyone maintaining complex async codebases.➡️ dotnet watch + Aspire integration: Automatic crash recovery and smoother hot reload make the inner dev loop noticeably faster and less frustrating.
➡️ Signed official container images: Microsoft now cryptographically signs .NET container images via the Notary Project. This is a serious supply chain security win for enterprise and regulated environments.
➡️ Smaller SDK + native Zstd compression: Deduplicated installers on Linux/macOS and better System.Text.Json control round out a very pragmatic release.
Overall, Preview 3 feels focused on “make developers’ lives better” rather than flashy new syntax. Highly recommended for early testing.
Download: dotnet.microsoft.com/download/dotnet/11.0
📩 Other Notable Updates
These are worth a quick read if you haven’t already!
➡️ .NET and .NET Framework April 2026 servicing releases updates: This roundup highlights the latest security patches and reliability fixes across supported versions, ensuring applications remain stable, secure, and fully supported. A quick check-in for developers to keep environments current with Microsoft’s regular Patch Tuesday updates.
➡️ ASP.NET Core 2.3 end of support announcement: ASP.NET Core 2.3 will reach end of support on April 13, 2027. After this date, it will receive no security patches, bug fixes, or technical support, even on .NET Framework. Time to migrate to .NET 10 (LTS) now.
➡️ Pin Clustering in .NET MAUI Maps: .NET MAUI Maps now supports pin clustering in .NET 11 Preview 3! Automatically group nearby pins into clusters on Android and iOS, with custom grouping via ClusteringIdentifier and tap handling. Say goodbye to overlapping pins.
✒️ Got a Minute?
Tell us what you loved, what you want more of, and how we can make .NETPro even better in 2026. This quick 1-minute survey helps shape future issues around what matters most to you.
🧑🏼💻 What .NET Experts Are Talking About
Inside the minds of .NET pros: Real-world experience, real insights!
➡️ Your Migration’s Source of Truth: The Modernization Assessment: Jeffrey Fritz shares why the assessment phase is the foundation of successful .NET and Java modernizations with GitHub Copilot. This powerful tool analyzes your codebase, surfaces blockers across upgrade, cloud readiness, and security domains, and generates actionable reports that drive accurate planning and execution. Essential reading for teams moving legacy apps to Azure.
➡️ Running AI agents safely in a microVM using docker sandbox: In this deep dive, Andrew Lock talks about how Docker’s microVM-based sandboxes isolate agents from your host, enabling autonomous workflows while protecting files, credentials, and networks. A practical guide to balancing productivity and safety when working with modern coding agents.
➡️ Monitoring .NET APIs and Microservices for Free (Uptime Kuma): In this video, Milan Jovanović shows you how to monitor your .NET APIs and microservices for free using Uptime Kuma. Learn how to set up this powerful self-hosted tool with Docker and connect it to your .NET health checks for real-time application monitoring.
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Tell us what you loved, what you want more of, and how we can make .NETPro even better in 2026. This quick 1-minute survey helps shape future issues around what matters most to you.
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And That’s a Wrap 🎬
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