A step-by-step guide to modernizing .NET applications with GitHub Copilot agent mode

In Visual Studio 2026, GitHub Copilot app modernization runs an upgrade or Azure migration as an agent session instead of a manual version bump. The agent produces three files as it works: an assessment.md report of outdated packages and breaking changes, an editable plan.md with the proposed upgrade steps, and a tasks.md log that tracks each step as it executes.

Human approval happens at plan.md: only after that file is reviewed does the agent apply any change. If it hits an error it can’t resolve, it stops and asks for input instead of guessing.

Fichamento

#

• Two entry points start a session: right-click the project in Solution Explorer and choose Modernize, or type @modernize in Copilot Chat.
• The assessment stage lists outdated NuGet packages with recommended target versions, project count and upgrade complexity, and an API analysis of potential breaking changes, before anything is touched.
• The plan.md file is fully editable: you can add context, reorder steps, or exclude specific projects before approving the upgrade.
• During execution, Copilot runs a fix-and-test loop on build errors and commits major changes to Git as it goes, so each step is a separate, revertible commit.
• The Azure migration path runs the same assess-plan-execute structure: a cloud readiness scan for framework compatibility and identity gaps, an editable migration plan, then automated CVE scans and safe version replacements before deployment.
• The final deployment step provisions resources, configures monitoring and logging, and secures identities without hand-written infrastructure scripts.