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…
安装
npx skills add dotnet/skills --skill migrate-dotnet8-to-dotnet9npx skills add dotnet/skills --skill migrate-dotnet8-to-dotnet9 -a claude-code -gnpx skills add dotnet/skills --skill migrate-dotnet8-to-dotnet9 -a codex -ggemini skills install https://github.com/dotnet/skills.git --path plugins/dotnet-upgrade/skills/migrate-dotnet8-to-dotnet9gh skill install dotnet/skills migrate-dotnet8-to-dotnet9git clone --depth 1 https://github.com/dotnet/skills /tmp/dotnet__skills
mkdir -p ~/.claude/skills ~/.agents/skills
cp -R /tmp/dotnet__skills/plugins/dotnet-upgrade/skills/migrate-dotnet8-to-dotnet9 ~/.claude/skills/migrate-dotnet8-to-dotnet9 # Claude Code
cp -R /tmp/dotnet__skills/plugins/dotnet-upgrade/skills/migrate-dotnet8-to-dotnet9 ~/.agents/skills/migrate-dotnet8-to-dotnet9 # Codex, Cursor, Gemini CLI, Copilot, OpenCode