Aspnet Core | Package file

Version 49f948fa.bb1 · Apache-2.0. This preview displays packaged text and does not execute code. Treat the contents as untrusted instructions.

Versioning And Upgrades

Primary docs: - https://learn.microsoft.com/aspnet/core/release-notes/ - https://learn.microsoft.com/aspnet/core/release-notes/aspnetcore-10.0 - https://learn.microsoft.com/aspnet/core/release-notes/aspnetcore-9.0 - https://github.com/dotnet/AspNetCore.Docs/tree/main/aspnetcore/breaking-changes

Versioning Default

For new production apps in March 2026, prefer net10.0
For existing apps, match the repository's target framework unless the task is explicitly an upgrade
Before using a new API, confirm it exists in the target framework

Upgrade Workflow

Identify the current target framework and SDK
Read the "What's new" and breaking-changes pages for each version hop
Compile and resolve obsoletions intentionally
Re-run integration tests and auth flows
Re-test deployment-specific behavior such as proxies, cookies, and static assets

High-Value Breaking-Change Checks

When moving to ASP.NET Core 10, watch for:

cookie login redirects disabled for known API endpoints
WithOpenApi deprecation
WebHostBuilder, IWebHost, and WebHost obsolescence
Razor runtime compilation obsolescence

When moving to ASP.NET Core 9, watch for:

ValidateOnBuild and ValidateScopes enabled in development when using HostBuilder
middleware constructor expectations and DI validation changes

When moving to ASP.NET Core 8, watch for:

Minimal API IFormFile antiforgery requirements
AddRateLimiter() and AddHttpLogging() requirements when corresponding middleware is used

Migration Principles

Prefer migration to the modern hosting model when touching startup extensively
Remove compatibility shims only after tests confirm behavior
Avoid mixing new framework idioms with old startup architecture in a half-migrated state
Keep one authoritative target framework in project files unless multi-targeting is deliberate

Preview Feature Rule