dotnet · gewarren · Aug 19, 2026 · Aug 17, 2026 · Aug 17, 2026 · Aug 17, 2026
diff --git a/.openpublishing.publish.config.json b/.openpublishing.publish.config.json
@@ -55,7 +55,7 @@
     {
       "path_to_root": "_csharpstandard",
       "url": "https://github.com/dotnet/csharpstandard",
-      "branch": "alpha-v12",
+      "branch": "alpha-v13",
       "include_in_build": true,
       "branch_mapping": {}
     },

diff --git a/.openpublishing.redirection.csharp.json b/.openpublishing.redirection.csharp.json
@@ -590,6 +590,30 @@
       "source_path_from_root": "/docs/csharp/language-reference/compiler-messages/cs7000.md",
       "redirect_url": "/dotnet/csharp/language-reference/compiler-messages/using-directive-errors"
     },
+    {
+      "source_path_from_root": "/docs/csharp/language-reference/compiler-messages/cs8124.md",
+      "redirect_url": "/dotnet/csharp/language-reference/compiler-messages/tuple-errors"
+    },
+    {
+      "source_path_from_root": "/docs/csharp/language-reference/compiler-messages/cs8125.md",
+      "redirect_url": "/dotnet/csharp/language-reference/compiler-messages/tuple-errors"
+    },
+    {
+      "source_path_from_root": "/docs/csharp/language-reference/compiler-messages/cs8127.md",
+      "redirect_url": "/dotnet/csharp/language-reference/compiler-messages/tuple-errors"
+    },
+    {
+      "source_path_from_root": "/docs/csharp/language-reference/compiler-messages/cs8139.md",
+      "redirect_url": "/dotnet/csharp/language-reference/compiler-messages/tuple-errors"
+    },
+    {
+      "source_path_from_root": "/docs/csharp/language-reference/compiler-messages/cs8140.md",
+      "redirect_url": "/dotnet/csharp/language-reference/compiler-messages/tuple-errors"
+    },
+    {
+      "source_path_from_root": "/docs/csharp/language-reference/compiler-messages/cs8141.md",
+      "redirect_url": "/dotnet/csharp/language-reference/compiler-messages/tuple-errors"
+    },
     {
       "source_path_from_root": "/docs/csharp/language-reference/compiler-messages/cs8145.md",
       "redirect_url": "/dotnet/csharp/language-reference/compiler-messages/property-declaration-errors"
@@ -638,6 +662,10 @@
       "source_path_from_root": "/docs/csharp/language-reference/compiler-messages/cs8178.md",
       "redirect_url": "/dotnet/csharp/language-reference/compiler-messages/async-await-errors"
     },
+    {
+      "source_path_from_root": "/docs/csharp/language-reference/compiler-messages/cs8210.md",
+      "redirect_url": "/dotnet/csharp/language-reference/compiler-messages/tuple-errors"
+    },
     {
       "source_path_from_root": "/docs/csharp/language-reference/compiler-messages/cs8373.md",
       "redirect_url": "/dotnet/csharp/language-reference/compiler-messages/ref-modifiers-errors"

diff --git a/docfx.json b/docfx.json
@@ -49,7 +49,6 @@
             },
             {
                 "files": [
-                    "csharp-13.0/*.md",
                     "csharp-14.0/*.md",
                     "csharp-15.0/*.md",
                     "unsafe-evolution.md"
@@ -502,8 +501,7 @@
                 "docs/visual-basic/**/**.{md,yml}": "wiwagn"
             },
             "ms.date": {
-                "_csharpstandard/standard/*.md": "08/12/2026",
-                "_csharplang/proposals/csharp-13.0/*.md": "10/31/2024",
+                "_csharpstandard/standard/*.md": "08/19/2026",
                 "_csharplang/proposals/csharp-14.0/*.md": "08/06/2025",
                 "_csharplang/proposals/csharp-15.0/*.md": "08/12/2026",
                 "_csharplang/proposals/*.md": "08/12/2026",
@@ -615,15 +613,6 @@
                 "_csharpstandard/standard/standard-library.md": "Standard library",
                 "_csharpstandard/standard/documentation-comments.md": "Documentation comments",
                 "_csharpstandard/standard/Bibliography.md": "Bibliography",
-                "_csharplang/proposals/csharp-13.0/collection-expressions-better-conversion.md": "Better conversion from collection expression",
-                "_csharplang/proposals/csharp-13.0/esc-escape-sequence.md": "String/Character escape sequence '\\e'",
-                "_csharplang/proposals/csharp-13.0/lock-object.md": "Obey lock object semantics for lock statements",
-                "_csharplang/proposals/csharp-13.0/method-group-natural-type-improvements.md": "Method group natural type improvements",
-                "_csharplang/proposals/csharp-13.0/params-collections.md": "Params collections",
-                "_csharplang/proposals/csharp-13.0/ref-unsafe-in-iterators-async.md": "Allow ref and unsafe in iterators and async methods",
-                "_csharplang/proposals/csharp-13.0/ref-struct-interfaces.md": "Allow ref struct types to implement some interfaces",
-                "_csharplang/proposals/csharp-13.0/partial-properties.md": "All partial properties and indexers",
-                "_csharplang/proposals/csharp-13.0/overload-resolution-priority.md": "Overload resolution priority tiebreaker attribute",
                 "_csharplang/proposals/csharp-14.0/field-keyword.md": "The `field` contextual keyword",
                 "_csharplang/proposals/csharp-14.0/unbound-generic-types-in-nameof.md": "Unbound generic types in `nameof`",
                 "_csharplang/proposals/csharp-14.0/first-class-span-types.md": "First-class span types",
@@ -695,15 +684,6 @@
                 "_csharpstandard/standard/standard-library.md": "This appendix lists requirements of the specification library. The C# language relies on these types for some of its behavior.",
                 "_csharpstandard/standard/documentation-comments.md": "This appendix describes XML comments that are used to document your program.",
                 "_csharpstandard/standard/Bibliography.md": "This appendix lists external standards referenced in this specification.",
-                "_csharplang/proposals/csharp-13.0/collection-expressions-better-conversion.md": "Conversions from collection expressions match the element type before matching the collection type.",
-                "_csharplang/proposals/csharp-13.0/esc-escape-sequence.md" : "The sequence '\\e' is now interpreted as the 'ESC' character, character point '0x1b'",
-                "_csharplang/proposals/csharp-13.0/lock-object.md": "Special-case how `System.Threading.Lock` interacts with the `lock` keyword by calling its `EnterScope` method. Add static analysis warnings to prevent accidental misuse of the type where possible.",
-                "_csharplang/proposals/csharp-13.0/method-group-natural-type-improvements.md": "This proposal refines the determination of the natural type of a method group by considering candidates scope-by-scope and pruning at each scope.",
-                "_csharplang/proposals/csharp-13.0/params-collections.md": "Allow the `params` modifier on collection types beyond arrays, including `IEnumerable` types.",
-                "_csharplang/proposals/csharp-13.0/ref-unsafe-in-iterators-async.md": "This proposal modifies restrictions to enable ref local variables and unsafe blocks in iterators and async methods",
-                "_csharplang/proposals/csharp-13.0/ref-struct-interfaces.md": "This proposal provides features that enable interface authors to allow `ref struct` types to implement a particular interface",
-                "_csharplang/proposals/csharp-13.0/partial-properties.md": "This proposal provides for partial properties and indexers, allowing the definition of a property or indexer to be split across multiple parts.",
-                "_csharplang/proposals/csharp-13.0/overload-resolution-priority.md": "This proposal introduces a new attribute, `OverloadResolutionPriorityAttribute`, that can be applied to methods to influence overload resolution.",
                 "_csharplang/proposals/csharp-14.0/field-keyword.md": "This proposal introduces a new keyword, `field`, that accesses the compiler generated backing field in a property accessor.",
                 "_csharplang/proposals/csharp-14.0/unbound-generic-types-in-nameof.md": "This proposal introduces the ability to use unbound generic types such as `List<>` in `nameof` expressions. The type argument isn't required.",
                 "_csharplang/proposals/csharp-14.0/first-class-span-types.md": "This proposal provides several implicit conversions to `Span<T>` and `ReadOnlySpan<T>` that enable library authors to have fewer overloads and developers to write code that resolves to faster Span based APIs",
@@ -744,7 +724,6 @@
             "titleSuffix": {
                 "docs/**/*.{md,yml}": ".NET",
                 "_csharpstandard/standard/*.md": "C# language specification",
-                "_csharplang/proposals/csharp-13.0/*.md": "C# feature specifications",
                 "_csharplang/proposals/csharp-14.0/*.md": "C# feature specifications",
                 "_csharplang/proposals/csharp-15.0/*.md": "C# feature specifications",
                 "_csharplang/proposals/*.md": "C# feature specifications (preview)",

diff --git a/docs/ai/evaluation/snippets/evaluate-with-reporting/TestAIWithReporting.csproj b/docs/ai/evaluation/snippets/evaluate-with-reporting/TestAIWithReporting.csproj
@@ -11,15 +11,15 @@
   <ItemGroup>
     <PackageReference Include="Azure.AI.OpenAI" Version="2.1.0" />
     <PackageReference Include="Azure.Identity" Version="1.21.0" />
-    <PackageReference Include="Microsoft.Extensions.AI.Abstractions" Version="10.8.0" />
-    <PackageReference Include="Microsoft.Extensions.AI.Evaluation" Version="10.8.0" />
-    <PackageReference Include="Microsoft.Extensions.AI.Evaluation.Quality" Version="10.8.0" />
-    <PackageReference Include="Microsoft.Extensions.AI.Evaluation.Reporting" Version="10.8.0" />
-    <PackageReference Include="Microsoft.Extensions.AI.OpenAI" Version="10.8.0" />
-    <PackageReference Include="microsoft.extensions.configuration" Version="10.0.10" />
-    <PackageReference Include="Microsoft.Extensions.Configuration.UserSecrets" Version="10.0.10" />
+    <PackageReference Include="Microsoft.Extensions.AI.Abstractions" Version="10.9.0" />
+    <PackageReference Include="Microsoft.Extensions.AI.Evaluation" Version="10.9.0" />
+    <PackageReference Include="Microsoft.Extensions.AI.Evaluation.Quality" Version="10.9.0" />
+    <PackageReference Include="Microsoft.Extensions.AI.Evaluation.Reporting" Version="10.9.0" />
+    <PackageReference Include="Microsoft.Extensions.AI.OpenAI" Version="10.9.0" />
+    <PackageReference Include="microsoft.extensions.configuration" Version="10.0.11" />
+    <PackageReference Include="Microsoft.Extensions.Configuration.UserSecrets" Version="10.0.11" />
     <PackageReference Include="Microsoft.NET.Test.Sdk" Version="18.8.1" />
-    <PackageReference Include="MSTest" Version="4.3.2" />
+    <PackageReference Include="MSTest" Version="4.3.3" />
   </ItemGroup>
 
   <ItemGroup>

diff --git a/docs/ai/how-to/snippets/access-data/Project.csproj b/docs/ai/how-to/snippets/access-data/Project.csproj
@@ -11,10 +11,10 @@
   <ItemGroup>
     <PackageReference Include="Azure.Identity" Version="1.21.0" />
     <PackageReference Include="Azure.AI.OpenAI" Version="2.1.0" />
-    <PackageReference Include="Microsoft.Extensions.AI" Version="10.8.3" />
-    <PackageReference Include="Microsoft.Extensions.AI.OpenAI" Version="10.8.3" />
-    <PackageReference Include="Microsoft.Extensions.Configuration" Version="10.0.10" />
-    <PackageReference Include="Microsoft.Extensions.Configuration.UserSecrets" Version="10.0.10" />
+    <PackageReference Include="Microsoft.Extensions.AI" Version="10.9.0" />
+    <PackageReference Include="Microsoft.Extensions.AI.OpenAI" Version="10.9.0" />
+    <PackageReference Include="Microsoft.Extensions.Configuration" Version="10.0.11" />
+    <PackageReference Include="Microsoft.Extensions.Configuration.UserSecrets" Version="10.0.11" />
 
   </ItemGroup>
 

diff --git a/docs/ai/how-to/snippets/hosted-app-auth/hosted-app-auth.csproj b/docs/ai/how-to/snippets/hosted-app-auth/hosted-app-auth.csproj
@@ -10,9 +10,9 @@
   <ItemGroup>
     <PackageReference Include="Azure.AI.OpenAI" Version="2.1.0" />
     <PackageReference Include="Azure.Identity" Version="1.21.0" />
-    <PackageReference Include="Microsoft.AspNetCore.OpenApi" Version="9.0.18" />
-    <PackageReference Include="Microsoft.Extensions.AI" Version="10.8.0" />
-    <PackageReference Include="Microsoft.Extensions.AI.OpenAI" Version="10.8.0" />
+    <PackageReference Include="Microsoft.AspNetCore.OpenApi" Version="9.0.19" />
+    <PackageReference Include="Microsoft.Extensions.AI" Version="10.9.0" />
+    <PackageReference Include="Microsoft.Extensions.AI.OpenAI" Version="10.9.0" />
     <PackageReference Include="Microsoft.Extensions.Azure" Version="1.14.0" />
   </ItemGroup>
 

diff --git a/docs/ai/ichatclient.md b/docs/ai/ichatclient.md
@@ -172,3 +172,10 @@ For more realistic, concrete implementations of `IChatClient`, see:
 > This feature is experimental and subject to change.
 
 Chat reduction helps manage conversation history by limiting the number of messages or summarizing older messages when the conversation exceeds a specified length. The `Microsoft.Extensions.AI` library provides reducers like <xref:Microsoft.Extensions.AI.MessageCountingChatReducer> that limits the number of non-system messages, and <xref:Microsoft.Extensions.AI.SummarizingChatReducer> that automatically summarizes older messages while preserving context.
+
+## Chat routing (experimental)
+
+> [!IMPORTANT]
+> This feature is experimental and subject to change.
+
+Chat routing helps direct each request to one of several chat clients&mdash;for example, based on the content of the request, or by failing over to another client when one is unavailable. The `Microsoft.Extensions.AI` library provides <xref:Microsoft.Extensions.AI.RoutingChatClient>, an abstract `IChatClient` that selects and invokes another client for each request, and <xref:Microsoft.Extensions.AI.FailoverChatClient>, an abstract subclass that retries with another client when an attempt fails before producing output. Samples include <xref:Microsoft.Extensions.AI.OrderedFailoverChatClient>, which fails over across an ordered sequence of clients, and <xref:Microsoft.Extensions.AI.SemanticRoutingChatClient>, which selects a client based on the semantic similarity of the request to example utterances.
diff --git a/docs/ai/quickstarts/snippets/image-generation/openai/ImagesOpenAI.csproj b/docs/ai/quickstarts/snippets/image-generation/openai/ImagesOpenAI.csproj
@@ -8,10 +8,10 @@
   </PropertyGroup>
 
   <ItemGroup>
-    <PackageReference Include="OpenAI" Version="2.12.0" />
-    <PackageReference Include="Microsoft.Extensions.AI.OpenAI" Version="10.7.0" />
-    <PackageReference Include="Microsoft.Extensions.Configuration" Version="10.0.9" />
-    <PackageReference Include="Microsoft.Extensions.Configuration.UserSecrets" Version="10.0.9" />
+    <PackageReference Include="OpenAI" Version="2.13.0" />
+    <PackageReference Include="Microsoft.Extensions.AI.OpenAI" Version="10.9.0" />
+    <PackageReference Include="Microsoft.Extensions.Configuration" Version="10.0.11" />
+    <PackageReference Include="Microsoft.Extensions.Configuration.UserSecrets" Version="10.0.11" />
   </ItemGroup>
 
 </Project>
diff --git a/docs/ai/quickstarts/snippets/mcp-client/MinimalMCPClient.csproj b/docs/ai/quickstarts/snippets/mcp-client/MinimalMCPClient.csproj
@@ -10,9 +10,9 @@
   <ItemGroup>
     <PackageReference Include="Azure.AI.OpenAI" Version="2.2.0-beta.5" />
     <PackageReference Include="Azure.Identity" Version="1.21.0" />
-    <PackageReference Include="Microsoft.Extensions.AI" Version="10.8.3" />
-    <PackageReference Include="Microsoft.Extensions.AI.OpenAI" Version="10.8.3" />
-    <PackageReference Include="ModelContextProtocol" Version="2.0.0" />
+    <PackageReference Include="Microsoft.Extensions.AI" Version="10.9.0" />
+    <PackageReference Include="Microsoft.Extensions.AI.OpenAI" Version="10.9.0" />
+    <PackageReference Include="ModelContextProtocol" Version="2.1.0" />
   </ItemGroup>
 
 </Project>
diff --git a/docs/ai/quickstarts/snippets/process-data/ProcessData.csproj b/docs/ai/quickstarts/snippets/process-data/ProcessData.csproj
@@ -10,12 +10,12 @@
 
   <ItemGroup>
     <PackageReference Include="Azure.AI.OpenAI" Version="2.8.0-beta.1" />
-    <PackageReference Include="Microsoft.Extensions.AI.OpenAI" Version="10.8.0" />
-    <PackageReference Include="Microsoft.Extensions.Configuration" Version="10.0.10" />
-    <PackageReference Include="Microsoft.Extensions.Configuration.UserSecrets" Version="10.0.10" />
+    <PackageReference Include="Microsoft.Extensions.AI.OpenAI" Version="10.9.0" />
+    <PackageReference Include="Microsoft.Extensions.Configuration" Version="10.0.11" />
+    <PackageReference Include="Microsoft.Extensions.Configuration.UserSecrets" Version="10.0.11" />
     <PackageReference Include="Microsoft.Extensions.DataIngestion" Version="10.1.1-preview.1.25612.2" />
     <PackageReference Include="Microsoft.Extensions.DataIngestion.Markdig" Version="10.1.1-preview.1.25612.2" />
-    <PackageReference Include="Microsoft.Extensions.Logging.Console" Version="10.0.10" />
+    <PackageReference Include="Microsoft.Extensions.Logging.Console" Version="10.0.11" />
     <PackageReference Include="Microsoft.ML.Tokenizers.Data.O200kBase" Version="2.0.0" />
     <PackageReference Include="Microsoft.SemanticKernel.Connectors.SqliteVec" Version="1.68.0-preview" />
   </ItemGroup>

diff --git a/docs/ai/snippets/microsoft-extensions-ai/AI.Shared/AI.Shared.csproj b/docs/ai/snippets/microsoft-extensions-ai/AI.Shared/AI.Shared.csproj
@@ -7,8 +7,8 @@
   </PropertyGroup>
 
   <ItemGroup>
-    <PackageReference Include="Microsoft.Extensions.AI" Version="10.8.3" />
-    <PackageReference Include="System.Threading.RateLimiting" Version="10.0.10" />
+    <PackageReference Include="Microsoft.Extensions.AI" Version="10.9.0" />
+    <PackageReference Include="System.Threading.RateLimiting" Version="10.0.11" />
   </ItemGroup>
 
 </Project>
diff --git a/...-extensions-ai/ConsoleAI.ConsumeClientMiddleware/ConsoleAI.ConsumeClientMiddleware.csproj b/...-extensions-ai/ConsoleAI.ConsumeClientMiddleware/ConsoleAI.ConsumeClientMiddleware.csproj
@@ -8,8 +8,8 @@
   </PropertyGroup>
 
   <ItemGroup>
-    <PackageReference Include="Microsoft.Extensions.Hosting" Version="10.0.10" />
-    <PackageReference Include="OllamaSharp" Version="5.4.27" />
+    <PackageReference Include="Microsoft.Extensions.Hosting" Version="10.0.11" />
+    <PackageReference Include="OllamaSharp" Version="5.4.30" />
     <ProjectReference Include="..\AI.Shared\AI.Shared.csproj" />
   </ItemGroup>
 

diff --git a/...icrosoft-extensions-ai/ConsoleAI.DependencyInjection/ConsoleAI.DependencyInjection.csproj b/...icrosoft-extensions-ai/ConsoleAI.DependencyInjection/ConsoleAI.DependencyInjection.csproj
@@ -8,9 +8,9 @@
   </PropertyGroup>
 
   <ItemGroup>
-    <PackageReference Include="OllamaSharp" Version="5.4.27" />
-    <PackageReference Include="Microsoft.Extensions.Hosting" Version="10.0.10" />
-    <PackageReference Include="Microsoft.Extensions.Caching.Memory" Version="10.0.10" />
+    <PackageReference Include="OllamaSharp" Version="5.4.30" />
+    <PackageReference Include="Microsoft.Extensions.Hosting" Version="10.0.11" />
+    <PackageReference Include="Microsoft.Extensions.Caching.Memory" Version="10.0.11" />
     <ProjectReference Include="..\AI.Shared\AI.Shared.csproj" />
   </ItemGroup>
 

diff --git a/...ts/microsoft-extensions-ai/ConsoleAI.StatelessStateful/ConsoleAI.StatelessStateful.csproj b/...ts/microsoft-extensions-ai/ConsoleAI.StatelessStateful/ConsoleAI.StatelessStateful.csproj
@@ -8,7 +8,7 @@
   </PropertyGroup>
 
   <ItemGroup>
-    <PackageReference Include="Microsoft.Extensions.AI.Abstractions" Version="10.8.3" />
+    <PackageReference Include="Microsoft.Extensions.AI.Abstractions" Version="10.9.0" />
   </ItemGroup>
 
   <ItemGroup>

diff --git a/docs/ai/vector-stores/snippets/chat-with-data/azure-openai/VectorDataAI.csproj b/docs/ai/vector-stores/snippets/chat-with-data/azure-openai/VectorDataAI.csproj
@@ -11,10 +11,10 @@
   <ItemGroup>
     <PackageReference Include="Azure.AI.OpenAI" Version="2.1.0" />
     <PackageReference Include="Azure.Identity" Version="1.21.0" />
-    <PackageReference Include="Microsoft.Extensions.AI.OpenAI" Version="10.8.3" />
-    <PackageReference Include="Microsoft.Extensions.Configuration" Version="10.0.10" />
-    <PackageReference Include="Microsoft.Extensions.Configuration.UserSecrets" Version="10.0.10" />
-    <PackageReference Include="CommunityToolkit.VectorData.InMemory" Version="1.0.0" />
+    <PackageReference Include="Microsoft.Extensions.AI.OpenAI" Version="10.9.0" />
+    <PackageReference Include="Microsoft.Extensions.Configuration" Version="10.0.11" />
+    <PackageReference Include="Microsoft.Extensions.Configuration.UserSecrets" Version="10.0.11" />
+    <PackageReference Include="CommunityToolkit.VectorData.InMemory" Version="1.0.1" />
   </ItemGroup>
 
 </Project>
diff --git a/docs/ai/vector-stores/snippets/conceptual/VectorStoreSnippets.csproj b/docs/ai/vector-stores/snippets/conceptual/VectorStoreSnippets.csproj
@@ -9,10 +9,10 @@
 
   <ItemGroup>
     <PackageReference Include="Azure.Search.Documents" Version="12.0.0" />
-    <PackageReference Include="Microsoft.Extensions.AI" Version="10.8.3" />
-    <PackageReference Include="Microsoft.Extensions.AI.OpenAI" Version="10.8.3" />
+    <PackageReference Include="Microsoft.Extensions.AI" Version="10.9.0" />
+    <PackageReference Include="Microsoft.Extensions.AI.OpenAI" Version="10.9.0" />
     <PackageReference Include="CommunityToolkit.VectorData.AzureAISearch" Version="1.0.0" />
-    <PackageReference Include="CommunityToolkit.VectorData.InMemory" Version="1.0.0" />
+    <PackageReference Include="CommunityToolkit.VectorData.InMemory" Version="1.0.1" />
     <PackageReference Include="CommunityToolkit.VectorData.Qdrant" Version="1.0.0" />
     <PackageReference Include="OpenAI" Version="2.*" />
   </ItemGroup>

diff --git a/docs/architecture/blazor-for-web-forms-developers/migration.md b/docs/architecture/blazor-for-web-forms-developers/migration.md
@@ -624,7 +624,7 @@ Because Blazor is built on .NET Core, there are considerations in ensuring suppo
 - Code Access Security (CAS)
 - Security Transparency
 
-For more information on techniques to identify necessary changes to support running on .NET Core, see [Port your code from .NET Framework to .NET Core](../../core/porting/index.md).
+For more information on techniques to identify necessary changes to support running on .NET Core, see [Port your code from .NET Framework to .NET](../../core/porting/framework-overview.md).
 
 ASP.NET Core is a reimagined version of ASP.NET and has some changes that may not initially seem obvious. The main changes are: