How to Migrate Your .NET 8 and 9 Apps to .NET 10 with Visual Studio and GitHub Copilot

This article provides a comprehensive guide for developers on migrating .NET 8 and .NET 9 applications to the latest .NET 10 LTS release, which is supported until November 2028. It highlights the end-of-support deadline for .NET 8/9 (November 2026) and emphasizes the simplicity of the upgrade. The core focus is on leveraging Visual Studio 2026's GitHub Copilot App Modernization feature, which automates NuGet package version upgrades, scans for API changes, and creates a detailed migration plan. The article explains the step-by-step flow: running an assessment, reviewing the plan, and letting Copilot apply changes, build the solution, and iterate until clean compilation. It also notes that while the upgrade is straightforward, some manual adjustments may be needed for dependencies and code patterns.