.NET 9 → .NET 10 Migration

Migrate a .NET 9 project or solution to .NET 10, systematically resolving all breaking changes. The outcome is a project targeting net10.0 that builds cleanly, passes tests, and accounts for every behavioral, source-incompatible, and binary-incompatible change introduced in the .NET 10 release.

When to Use

• Upgrading TargetFramework from net9.0 to net10.0
• Resolving build errors or new warnings after updating the .NET 10 SDK
• Adapting to behavioral changes in .NET 10 runtime, ASP.NET Core 10, or EF Core 10
• Updating CI/CD pipelines, Dockerfiles, or deployment scripts for .NET 10
• Migrating from the community System.Linq.Async package to the built-in System.Linq.AsyncEnumerable

When Not to Use

• The project already targets net10.0 and builds cleanly — migration is done
• Upgrading from .NET 8 or earlier — use the migrate-dotnet8-to-dotnet9 skill first to reach net9.0, then return to this skill for the net9.0 → net10.0 migration
• Migrating from .NET Framework — that is a separate, larger effort
• Greenfield projects that start on .NET 10 (no migration needed)