migrate-dotnet8-to-dotnet9

.NET 8 → .NET 9 Migration Migrate a .NET 8 project or solution to .NET 9, systematically resolving all breaking changes. The outcome is a project targeting net9.0 that builds cleanly, passes tests, and accounts for every behavioral, source-incompatible, and binary-incompatible change introduced in the .NET 9 release. When to Use Upgrading TargetFramework from net8.0 to net9.0 Resolving build errors or new warnings after updating the .NET 9 SDK Adapting to behavioral changes in .NET 9 runtime, ASP.NET Core 9, or EF Core 9 Replacing BinaryFormatter usage (now always throws at runtime) Updating CI/CD pipelines, Dockerfiles, or deployment scripts for .NET 9 When Not to Use The project already targets net9.0 and builds cleanly — migration is done. If the goal is to reach net10.0 , use the migrate-dotnet9-to-dotnet10 skill as the next step. Upgrading from .NET 7 or earlier — address the prior version breaking changes first Migrating from .NET Framework — that is a separate, larger effort Greenfield projects that start on .NET 9 (no migration needed) Show more Installs 904 Repository dotnet/skills GitHub Stars 5.1K First Seen Mar 12, 2026 Security Audits Gen Agent Trust Hub Pass Socket Pass Snyk Pass