Updates for February 2026 .NET Releases

.github/instructions/csharp.instructions.md

@@ -60,3 +60,7 @@ Other patterns:
 - Comments inside methods should explain "why," not "what".
 - Comments should provide context and rationale behind the code.
 - Avoid redundant comments that restate the code - not all code needs comments.
+
+## Testing
+
+- Do not add comments like `// Arrange`, `// Act`, or `// Assert` in unit tests.

.github/linters/.linkspector.yml

@@ -9,6 +9,7 @@ dirs:
   - .
   - .github
 excludedDirs:
+  - eng/announcement-templates
   - eng/readme-templates
 ignorePatterns:
   - pattern: "^https://github.com/microsoft/mcr.*$"

.github/workflows/lint-code-base.yml

@@ -25,6 +25,6 @@ jobs:
         uses: github/super-linter@v6 # https://github.com/github/super-linter
         env:
           DEFAULT_BRANCH: main
-          FILTER_REGEX_EXCLUDE: eng/docker-tools/.*|eng/readme-templates/.*|.portal-docs/.*
+          FILTER_REGEX_EXCLUDE: eng/announcement-templates/.*|eng/docker-tools/.*|eng/readme-templates/.*|.portal-docs/.*
           GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
           VALIDATE_MARKDOWN: true

eng/announcement-templates/Render.cs

@@ -0,0 +1,218 @@
+#!/usr/bin/env dotnet
+#:package Fluid.Core@2.31.0
+#:package Spectre.Console@0.54.1-alpha.0.26
+#:package System.CommandLine@2.0.2
+
+using System.CommandLine;
+using Fluid;
+using Spectre.Console;
+
+var renderCommand = new RenderTemplateCommand(templateFileInfo =>
+{
+    if (!templateFileInfo.Exists)
+    {
+        Console.Error.WriteLine($"Template file not found: {templateFileInfo.FullName}");
+        return 1;
+    }
+
+    if (!TemplateDefinitions.TemplateIsSupported(templateFileInfo))
+    {
+        Console.Error.WriteLine($"Unsupported template file: {templateFileInfo.Name}");
+        return 1;
+    }
+
+    // Parse the template first, so any errors are caught before prompting for input
+    var template = TemplateDefinitions.ParseTemplate(templateFileInfo, out var parseError);
+    if (template is null)
+    {
+        Console.Error.WriteLine($"Failed to parse template: {parseError}");
+        return 1;
+    }
+
+    // Display some helpful reference information right before prompting the user for input.
+    DisplayPatchTuesdayReferenceText();
+
+    // This will prompt the user for the template parameters.
+    TemplateContext context = TemplateDefinitions.GetTemplateContext(templateFileInfo);
+
+    // Finally, render the template with the provided parameters.
+    var result = template.Render(context);
+
+    AnsiConsole.WriteLine();
+    AnsiConsole.Write(new Rule("[green]Generated Announcement[/]"));
+    AnsiConsole.WriteLine();
+    Console.WriteLine(result);
+
+    return 0;
+});
+
+var parseResult = renderCommand.Parse(args);
+return parseResult.Invoke();
+
+
+static void DisplayPatchTuesdayReferenceText()
+{
+    AnsiConsole.WriteLine();
+    AnsiConsole.MarkupLine("[grey]Patch Tuesdays Reference:[/]");
+    for (int i = -4; i <= 4; i++)
+    {
+        var pt = DateOnly.GetPatchTuesday(i);
+        var label = i == 0 ? "this month" : i.ToString("+0;-0");
+        AnsiConsole.MarkupLine($"[grey]  {label,11}: {pt:yyyy-MM-dd}[/]");
+    }
+
+    AnsiConsole.WriteLine();
+}
+
+static class TemplateDefinitions
+{
+    // All supported templates and their associated context factories.
+    private static readonly Dictionary<string, Func<TemplateContext>> s_templateContexts = new()
+    {
+        ["alpine-floating-tag-update.md"] = AlpineFloatingTagTemplateParameters.ContextFactory,
+    };
+
+    public static TemplateContext GetTemplateContext(FileInfo templateFileInfo)
+    {
+        var contextFactory = s_templateContexts[templateFileInfo.Name];
+        var templateContext = contextFactory();
+        return templateContext;
+    }
+
+    public static IFluidTemplate? ParseTemplate(FileInfo templateFile, out string? error)
+    {
+        var parser = new FluidParser();
+        var templateText = File.ReadAllText(templateFile.FullName);
+
+        if (!parser.TryParse(templateText, out var template, out string? internalError))
+        {
+            error = internalError;
+            return null;
+        }
+
+        error = null;
+        return template;
+    }
+
+    public static bool TemplateIsSupported(FileInfo templateFile) =>
+        s_templateContexts.ContainsKey(templateFile.Name);
+}
+
+sealed class RenderTemplateCommand : RootCommand
+{
+    public RenderTemplateCommand(Func<FileInfo, int> handler) : base("Render announcement template")
+    {
+        var templateFileArgument = new Argument<FileInfo>("templateFile")
+        {
+            Description = "The template file to read and display on the console",
+        };
+        Arguments.Add(templateFileArgument);
+
+        SetAction(parseResult =>
+        {
+            var templateFileResult = parseResult.GetValue(templateFileArgument);
+            if (parseResult.Errors.Count == 0 && templateFileResult is FileInfo validTemplateFile)
+            {
+                return handler(validTemplateFile);
+            }
+
+            if (parseResult.Errors.Count > 0)
+            {
+                foreach (var error in parseResult.Errors)
+                    Console.Error.WriteLine(error.Message);
+
+                return 1;
+            }
+
+            // Show help text
+            Parse("-h").Invoke();
+
+            return 0;
+        });
+    }
+}
+
+sealed record AlpineFloatingTagTemplateParameters(
+    string NewVersion,
+    string OldVersion,
+    DateTime PublishDate,
+    DateTime ReleaseDate,
+    DateTime EolDate,
+    string PublishDiscussionUrl,
+    string DotnetExampleVersion)
+{
+    public static Func<TemplateContext> ContextFactory { get; } = () =>
+    {
+        var model = PromptForInput();
+        return new TemplateContext(model);
+    };
+
+    public static AlpineFloatingTagTemplateParameters PromptForInput()
+    {
+        var newVersion = AnsiConsole.Prompt(
+            new TextPrompt<string>("New Alpine version:")
+                .DefaultValue("3.XX"));
+
+        var oldVersion = AnsiConsole.Prompt(
+            new TextPrompt<string>("Previous Alpine version:")
+                .DefaultValue("3.XX"));
+
+        var publishDate = AnsiConsole.Prompt(
+            new TextPrompt<DateOnly>($"When was Alpine {newVersion} published?")
+                .DefaultValue(DateOnly.GetPatchTuesday(-1)));
+
+        const string DiscussionQueryLink = "https://github.com/dotnet/dotnet-docker/discussions/categories/announcements?discussions_q=is%3Aopen+category%3AAnnouncements+alpine";
+        var publishDiscussionUrl = AnsiConsole.Prompt(
+            new TextPrompt<string>($"Link to announcement for publishing Alpine {newVersion} images (see {DiscussionQueryLink}):"));
+
+        var releaseDate = AnsiConsole.Prompt(
+            new TextPrompt<DateOnly>($"When were floating tags moved from Alpine {oldVersion} to {newVersion}?")
+                .DefaultValue(DateOnly.GetPatchTuesday(0)));
+
+        var eolDate = AnsiConsole.Prompt(
+            new TextPrompt<DateOnly>($"When will we stop publishing Alpine {oldVersion} images?")
+                .DefaultValue(DateOnly.GetPatchTuesday(3)));
+
+        var dotnetExampleVersion = AnsiConsole.Prompt(
+            new TextPrompt<string>(".NET example version for tags:")
+                .DefaultValue("10.0"));
+
+        return new AlpineFloatingTagTemplateParameters(
+            newVersion,
+            oldVersion,
+            publishDate.ToDateTime(TimeOnly.MinValue),
+            releaseDate.ToDateTime(TimeOnly.MinValue),
+            eolDate.ToDateTime(TimeOnly.MinValue),
+            publishDiscussionUrl,
+            dotnetExampleVersion);
+    }
+}
+
+internal static class DateOnlyExtensions
+{
+    extension(DateOnly date)
+    {
+        /// <summary>
+        /// Gets the Patch Tuesday (second Tuesday of the month) for a month
+        /// relative to the current month.
+        /// </summary>
+        /// <param name="offset">
+        /// The number of months from the current month.
+        /// 0 = this month, 1 = next month, -3 = three months ago.
+        /// </param>
+        /// <returns>The date of Patch Tuesday for the target month.</returns>
+        public static DateOnly GetPatchTuesday(int offset = 0)
+        {
+            var today = DateOnly.FromDateTime(DateTime.Today);
+            var targetMonth = today.AddMonths(offset);
+            var firstOfMonth = new DateOnly(targetMonth.Year, targetMonth.Month, 1);
+
+            // Find the first Tuesday
+            var daysUntilTuesday = ((int)DayOfWeek.Tuesday - (int)firstOfMonth.DayOfWeek + 7) % 7;
+            var firstTuesday = firstOfMonth.AddDays(daysUntilTuesday);
+
+            // Second Tuesday is 7 days later
+            return firstTuesday.AddDays(7);
+        }
+    }
+}

eng/announcement-templates/alpine-floating-tag-update.md

@@ -0,0 +1,23 @@
+# Alpine Floating Tags Updated to Alpine {{ NewVersion }}
+
+In {{ PublishDate | date: "%B %Y" }}, [Alpine {{ NewVersion }} container images were published]({{ PublishDiscussionUrl }}). For today's {{ ReleaseDate | date: "%B %Y" }} .NET release, all Alpine floating tags now point to Alpine {{ NewVersion }} instead of Alpine {{ OldVersion }} according to our [tagging policy](https://github.com/dotnet/dotnet-docker/blob/main/documentation/supported-tags.md).
+
+Per the [.NET Docker platform support policy](https://github.com/dotnet/dotnet-docker/blob/main/documentation/supported-platforms.md#linux), Alpine {{ OldVersion }} images will no longer be maintained starting on {{ EolDate | date: "%B %-d, %Y" }} (3 months after Alpine {{ NewVersion }} images were released).
+
+## Details
+
+Please review the [Alpine {{ NewVersion }} changelog](https://alpinelinux.org/posts/Alpine-{{ NewVersion }}.0-released.html) for more details on changes that were made in this version of Alpine.
+
+The affected floating tags use this naming pattern:
+
+* `<version>-alpine` (e.g. `{{ DotnetExampleVersion }}-alpine`)
+* `<version>-alpine-<variant>` (e.g. `{{ DotnetExampleVersion }}-alpine-extra`)
+* `<version>-alpine-<arch>` (e.g. `{{ DotnetExampleVersion }}-alpine-amd64`)
+* `<version>-alpine-<variant>-<arch>` (e.g. `{{ DotnetExampleVersion }}-alpine-extra-amd64`)
+
+The following image repos have been updated:
+
+* dotnet/sdk - [Microsoft Artifact Registry](https://mcr.microsoft.com/product/dotnet/sdk/about)
+* dotnet/aspnet - [Microsoft Artifact Registry](https://mcr.microsoft.com/product/dotnet/aspnet/about)
+* dotnet/runtime - [Microsoft Artifact Registry](https://mcr.microsoft.com/product/dotnet/runtime/about)
+* dotnet/runtime-deps - [Microsoft Artifact Registry](https://mcr.microsoft.com/product/dotnet/runtime-deps/about)

eng/mcr-tags-metadata-templates/aspnet-tags.yml

@@ -1,4 +1,20 @@
 $(McrTagsYmlRepo:aspnet)
+$(McrTagsYmlTagGroup:11.0-preview-resolute|.NET 11 Preview Tags)
+$(McrTagsYmlTagGroup:11.0-preview-resolute-chiseled|.NET 11 Preview Tags)
+$(McrTagsYmlTagGroup:11.0-preview-resolute-chiseled-extra|.NET 11 Preview Tags)
+$(McrTagsYmlTagGroup:11.0-preview-resolute-chiseled-composite|.NET 11 Preview Tags)
+$(McrTagsYmlTagGroup:11.0-preview-resolute-chiseled-composite-extra|.NET 11 Preview Tags)
+$(McrTagsYmlTagGroup:11.0-preview-alpine3.23|.NET 11 Preview Tags)
+$(McrTagsYmlTagGroup:11.0-preview-alpine3.23-extra|.NET 11 Preview Tags)
+$(McrTagsYmlTagGroup:11.0-preview-alpine3.23-composite|.NET 11 Preview Tags)
+$(McrTagsYmlTagGroup:11.0-preview-alpine3.23-composite-extra|.NET 11 Preview Tags)
+$(McrTagsYmlTagGroup:11.0-preview-azurelinux3.0|.NET 11 Preview Tags)
+$(McrTagsYmlTagGroup:11.0-preview-azurelinux3.0-distroless|.NET 11 Preview Tags)
+$(McrTagsYmlTagGroup:11.0-preview-azurelinux3.0-distroless-extra|.NET 11 Preview Tags)
+$(McrTagsYmlTagGroup:11.0-preview-azurelinux3.0-distroless-composite|.NET 11 Preview Tags)
+$(McrTagsYmlTagGroup:11.0-preview-azurelinux3.0-distroless-composite-extra|.NET 11 Preview Tags)
+$(McrTagsYmlTagGroup:11.0-preview-nanoserver-ltsc2025|.NET 11 Preview Tags)
+$(McrTagsYmlTagGroup:11.0-preview-windowsservercore-ltsc2025|.NET 11 Preview Tags)
 $(McrTagsYmlTagGroup:10.0-noble)
 $(McrTagsYmlTagGroup:10.0-noble-chiseled)
 $(McrTagsYmlTagGroup:10.0-noble-chiseled-extra)

eng/mcr-tags-metadata-templates/runtime-deps-tags.yml

@@ -1,4 +1,12 @@
 $(McrTagsYmlRepo:runtime-deps)
+$(McrTagsYmlTagGroup:11.0-preview-resolute|.NET 11 Preview Tags)
+$(McrTagsYmlTagGroup:11.0-preview-resolute-chiseled|.NET 11 Preview Tags)
+$(McrTagsYmlTagGroup:11.0-preview-resolute-chiseled-extra|.NET 11 Preview Tags)
+$(McrTagsYmlTagGroup:11.0-preview-alpine3.23|.NET 11 Preview Tags)
+$(McrTagsYmlTagGroup:11.0-preview-alpine3.23-extra|.NET 11 Preview Tags)
+$(McrTagsYmlTagGroup:11.0-preview-azurelinux3.0|.NET 11 Preview Tags)
+$(McrTagsYmlTagGroup:11.0-preview-azurelinux3.0-distroless|.NET 11 Preview Tags)
+$(McrTagsYmlTagGroup:11.0-preview-azurelinux3.0-distroless-extra|.NET 11 Preview Tags)
 $(McrTagsYmlTagGroup:10.0-noble)
 $(McrTagsYmlTagGroup:10.0-noble-chiseled)
 $(McrTagsYmlTagGroup:10.0-noble-chiseled-extra)

eng/mcr-tags-metadata-templates/runtime-tags.yml

@@ -1,4 +1,14 @@
 $(McrTagsYmlRepo:runtime)
+$(McrTagsYmlTagGroup:11.0-preview-resolute|.NET 11 Preview Tags)
+$(McrTagsYmlTagGroup:11.0-preview-resolute-chiseled|.NET 11 Preview Tags)
+$(McrTagsYmlTagGroup:11.0-preview-resolute-chiseled-extra|.NET 11 Preview Tags)
+$(McrTagsYmlTagGroup:11.0-preview-alpine3.23|.NET 11 Preview Tags)
+$(McrTagsYmlTagGroup:11.0-preview-alpine3.23-extra|.NET 11 Preview Tags)
+$(McrTagsYmlTagGroup:11.0-preview-azurelinux3.0|.NET 11 Preview Tags)
+$(McrTagsYmlTagGroup:11.0-preview-azurelinux3.0-distroless|.NET 11 Preview Tags)
+$(McrTagsYmlTagGroup:11.0-preview-azurelinux3.0-distroless-extra|.NET 11 Preview Tags)
+$(McrTagsYmlTagGroup:11.0-preview-nanoserver-ltsc2025|.NET 11 Preview Tags)
+$(McrTagsYmlTagGroup:11.0-preview-windowsservercore-ltsc2025|.NET 11 Preview Tags)
 $(McrTagsYmlTagGroup:10.0-noble)
 $(McrTagsYmlTagGroup:10.0-noble-chiseled)
 $(McrTagsYmlTagGroup:10.0-noble-chiseled-extra)

eng/mcr-tags-metadata-templates/sdk-tags.yml

@@ -1,4 +1,12 @@
 $(McrTagsYmlRepo:sdk)
+$(McrTagsYmlTagGroup:11.0-preview-resolute|.NET 11 Preview Tags)
+$(McrTagsYmlTagGroup:11.0-preview-resolute-aot|.NET 11 Preview Tags)
+$(McrTagsYmlTagGroup:11.0-preview-alpine3.23|.NET 11 Preview Tags)
+$(McrTagsYmlTagGroup:11.0-preview-alpine3.23-aot|.NET 11 Preview Tags)
+$(McrTagsYmlTagGroup:11.0-preview-azurelinux3.0|.NET 11 Preview Tags)
+$(McrTagsYmlTagGroup:11.0-preview-azurelinux3.0-aot|.NET 11 Preview Tags)
+$(McrTagsYmlTagGroup:11.0-preview-nanoserver-ltsc2025|.NET 11 Preview Tags)
+$(McrTagsYmlTagGroup:11.0-preview-windowsservercore-ltsc2025|.NET 11 Preview Tags)
 $(McrTagsYmlTagGroup:10.0-noble)
 $(McrTagsYmlTagGroup:10.0-noble-aot)
 $(McrTagsYmlTagGroup:10.0-alpine3.22)

eng/pipelines/dotnet-core-samples-pr.yml

@@ -15,9 +15,6 @@ pr:
 
 variables:
 - template: /eng/pipelines/variables/samples.yml@self
-- name: publishEolAnnotations
-  value: false
-  readonly: true
 
 resources:
   repositories:

eng/pipelines/dotnet-core-samples.yml

@@ -14,9 +14,6 @@ parameters:
 variables:
 - template: /eng/pipelines/variables/samples.yml@self
 - template: /eng/docker-tools/templates/variables/dotnet/secrets.yml@self
-- name: publishEolAnnotations
-  value: true
-  readonly: true
 
 resources:
   repositories:

eng/pipelines/pipelines/update-dependencies-internal.yml

@@ -1,8 +1,8 @@
 parameters:
-# Build ID of the .NET staging pipeline to fetch updates from. This can be a
-# pipeline run of the real staging pipeline or the staging test pipeline, but
-# the stagingStorageAccount parameter must match which pipeline is used here.
-- name: buildId
+# Stage container name (e.g., "stage-1234567") to fetch updates from. This can be
+# from the real staging pipeline or the staging test pipeline, but the
+# stagingStorageAccount parameter must match which pipeline is used here.
+- name: stageContainer
   type: string
   default: ""
 # Staging storage account for .NET release artifacts
@@ -42,7 +42,7 @@ extends:
               inlineScript: >-
                 dotnet run --project eng/update-dependencies/update-dependencies.csproj --
                 from-staging-pipeline
-                ${{ parameters.buildId }}
+                ${{ parameters.stageContainer }}
                 --mode Remote
                 --azdo-organization "$(System.CollectionUri)"
                 --azdo-project "$(System.TeamProject)"

eng/pipelines/update-dependencies-internal-official.yml

@@ -21,7 +21,7 @@ resources:
 extends:
   template: /eng/pipelines/pipelines/update-dependencies-internal.yml@self
   parameters:
-    buildId: "$(resources.pipeline.dotnet-staging-pipeline.runID)"
+    stageContainer: "stage-$(resources.pipeline.dotnet-staging-pipeline.runID)"
     stagingStorageAccount: "dotnetstage"
     targetBranch: "$(targetBranch)"
     gitServiceConnectionName: "$(updateDepsInt.serviceConnectionName)"

eng/pipelines/update-dependencies-internal-unofficial.yml

@@ -24,7 +24,7 @@ resources:
 extends:
   template: /eng/pipelines/pipelines/update-dependencies-internal.yml@self
   parameters:
-    buildId: "$(resources.pipeline.dotnet-staging-pipeline.runID)"
+    stageContainer: "stage-$(resources.pipeline.dotnet-staging-pipeline.runID)"
     stagingStorageAccount: "dotnetstage"
     targetBranch: "${{ parameters.targetBranch }}"
     gitServiceConnectionName: "$(updateDepsInt-test.serviceConnectionName)"

eng/pipelines/update-dependencies-official.yml

@@ -16,9 +16,7 @@ parameters:
   - name: updateDotnet
     displayName: Update .NET?
     type: boolean
-    # Updates are disabled until .NET 11 Alpha images are added.
-    # Re-enable when https://github.com/dotnet/dotnet-docker/issues/6824 is resolved.
-    default: false
+    default: true
   - name: updateAspire
     displayName: Update Aspire Dashboard?
     type: boolean