migrate-dotnet8-to-dotnet9
Migrate a .NET 8 project to .NET 9 and resolve all breaking changes. USE FOR: upgrading TargetFramework from net8.0 to net9.0, fixing build errors after updating the .NET 9 SDK, resolving behavioral changes in .NET 9 / C# 13 / ASP.NET Core 9 / EF Core 9, replacing BinaryFormatter (now always throws), resolving SYSLIB0054-SYSLIB0057, adapting to params span overload resolution, fixing C# 13 compiler changes, updating HttpClientFactory for SocketsHttpHandler, and resolving EF Core 9 migration/Cosmos DB changes. DO NOT USE FOR: .NET Framework migrations, upgrading from .NET 7 or earlier, greenfield .NET 9 projects, or cosmetic modernization unrelated to the upgrade.
- License
- MIT
Pinned to revision 1f6ed35d48cb, so it is the text this page describes rather than whatever the author pushed since.
Files
- skills/migrate-dotnet8-to-dotnet9/SKILL.md
- skills/migrate-dotnet8-to-dotnet9/references/aspnet-core-dotnet8to9.md
- skills/migrate-dotnet8-to-dotnet9/references/containers-interop-dotnet8to9.md
- skills/migrate-dotnet8-to-dotnet9/references/core-libraries-dotnet8to9.md
- skills/migrate-dotnet8-to-dotnet9/references/cryptography-dotnet8to9.md
- skills/migrate-dotnet8-to-dotnet9/references/csharp-compiler-dotnet8to9.md
- skills/migrate-dotnet8-to-dotnet9/references/deployment-runtime-dotnet8to9.md
- skills/migrate-dotnet8-to-dotnet9/references/efcore-dotnet8to9.md
- skills/migrate-dotnet8-to-dotnet9/references/sdk-msbuild-dotnet8to9.md
- skills/migrate-dotnet8-to-dotnet9/references/serialization-networking-dotnet8to9.md
- skills/migrate-dotnet8-to-dotnet9/references/winforms-wpf-dotnet8to9.md
Every link opens the file at its source, pinned to the revision this page describes.