Add migration guidance for existing F# MVC applications upgrading from .NET 10 to .NET 11 (#37686)

aspnetcore/migration/100-to-110.md

@@ -1,7 +1,8 @@
 ---
 title: Migrate from ASP.NET Core in .NET 10 to ASP.NET Core in .NET 11
+ai-usage: ai-assisted
 description: Learn how to migrate an ASP.NET Core in .NET 10 to ASP.NET Core in .NET 11.
-ms.date: 07/15/2026
+ms.date: 10/19/2026
 uid: migration/100-to-110
 ---
 # Migrate from ASP.NET Core in .NET 10 to ASP.NET Core in .NET 11
@@ -75,6 +76,10 @@ In the project file, update each [`Microsoft.AspNetCore.*`](https://www.nuget.or
 
 [!INCLUDE[](~/migration/100-to-110/includes/security.md)]
 
+## ASP.NET Core MVC
+
+[!INCLUDE[](~/migration/100-to-110/includes/mvc.md)]
+
 ## Breaking changes
 
 Use the articles in [Breaking changes in .NET](/dotnet/core/compatibility/breaking-changes) to find breaking changes that might apply when upgrading an app to a newer version of .NET.

aspnetcore/migration/100-to-110/includes/mvc.md

@@ -0,0 +1,73 @@
+### Upgrading F# MVC applications from .NET 10 to .NET 11
+
+Newly generated .NET 11 F# MVC projects already include build- and publish-time Razor compilation and view assembly registration. The following steps apply when migrating an existing F# MVC application from .NET 10 or earlier.
+
+F# MVC projects generated by earlier templates use the [`Microsoft.AspNetCore.Mvc.Razor.RuntimeCompilation` NuGet package](https://www.nuget.org/packages/Microsoft.AspNetCore.Mvc.Razor.RuntimeCompilation) and call <xref:Microsoft.Extensions.DependencyInjection.RazorRuntimeCompilationMvcBuilderExtensions.AddRazorRuntimeCompilation*>. Razor Runtime Compilation is obsolete in .NET 10 or later ([breaking change announcement](/aspnet/core/breaking-changes/10/razor-runtime-compilation-obsolete)). Unlike C# MVC projects, F# projects can't use the Razor source generator directly. Removing Runtime Compilation without configuring compilation causes the app to build successfully but fail at runtime when a view is requested with an <xref:System.InvalidOperationException>.
+
+To upgrade an existing F# MVC project:
+
+1. Remove the `Microsoft.AspNetCore.Mvc.Razor.RuntimeCompilation` package reference from the project file (`.fsproj`).
+1. In `Program.fs`, remove the call to `AddRazorRuntimeCompilation`.
+1. Configure Razor compilation in the project file:
+
+   ```xml
+   <PropertyGroup>
+     <UseRazorSourceGenerator>false</UseRazorSourceGenerator>
+     <RazorCompileOnBuild>true</RazorCompileOnBuild>
+     <RazorCompileOnPublish>true</RazorCompileOnPublish>
+   </PropertyGroup>
+   ```
+
+1. Add `MvcBuilderExtensions.fs` to the project file before `Program.fs`, as F# compilation order is significant:
+
+   ```xml
+   <ItemGroup>
+     <!-- Other F# source files -->
+     <Compile Include="MvcBuilderExtensions.fs" />
+     <Compile Include="Program.fs" />
+   </ItemGroup>
+   ```
+
+1. Add `MvcBuilderExtensions.fs`. The namespace must match the application's root namespace (for example, `Company.WebApplication1`):
+
+   ```fsharp
+   namespace Company.WebApplication1
+
+   open System
+   open System.IO
+   open System.Reflection
+   open System.Runtime.CompilerServices
+   open System.Runtime.Loader
+   open Microsoft.AspNetCore.Mvc.ApplicationParts
+   open Microsoft.Extensions.DependencyInjection
+
+   [<Extension>]
+   type MvcBuilderExtensions =
+       [<Extension>]
+       static member AddCompiledRazorViews(builder: IMvcBuilder) =
+           let applicationAssembly = Assembly.GetExecutingAssembly()
+           let viewsAssemblyName = $"{applicationAssembly.GetName().Name}.Views"
+           let viewsAssemblyPath =
+               Path.Combine(AppContext.BaseDirectory, $"{viewsAssemblyName}.dll")
+           let loadContext =
+               AssemblyLoadContext.GetLoadContext(applicationAssembly)
+
+           let viewsAssembly =
+               if File.Exists(viewsAssemblyPath) then
+                   loadContext.LoadFromAssemblyPath(viewsAssemblyPath)
+               else
+                   loadContext.LoadFromAssemblyName(AssemblyName(viewsAssemblyName))
+
+           builder.PartManager.ApplicationParts.Add(
+               CompiledRazorAssemblyPart(viewsAssembly))
+           builder
+   ```
+
+1. Register the compiled views in `Program.fs`:
+
+   ```fsharp
+       .AddControllersWithViews()
+       .AddCompiledRazorViews()
+   ```
+
+This configuration compiles Razor views during build and publish and registers the resulting views assembly with MVC. It avoids the obsolete Runtime Compilation dependency and allows view discovery at runtime.