diff --git a/README.md b/README.md
index 54075ff52e..86126bc6a4 100644
--- a/README.md
+++ b/README.md
@@ -236,6 +236,7 @@ The following community-contributed extensions are available in [`catalog.commun
 | MemoryLint | Agent memory governance tool: Automatically audits and fixes boundary conflicts between AGENTS.md and the constitution. | `process` | Read+Write | [memorylint](https://github.com/RbBtSn0w/spec-kit-extensions/tree/main/memorylint) |
 | Microsoft 365 Integration | Fetch Teams messages, meeting transcripts, and SharePoint/OneDrive files as local Markdown for spec generation | `integration` | Read+Write | [spec-kit-m365](https://github.com/BenBtg/spec-kit-m365) |
 | Multi-Model Review | Cross-model Spec Kit handoffs for spec authoring, implementation routing, and review. | `process` | Read+Write | [multi-model-review](https://github.com/formin/multi-model-review) |
+| .NET Framework to Modern .NET Migration | Orchestrate end-to-end .NET Framework to modern .NET migration across 7 phases, with SDD lifecycle integration | `process` | Read+Write | [spec-kit-fx-to-net](https://github.com/RogerBestMsft/spec-kit-FxToNet) |
 | Onboard | Contextual onboarding and progressive growth for developers new to spec-kit projects. Explains specs, maps dependencies, validates understanding, and guides the next step | `process` | Read+Write | [spec-kit-onboard](https://github.com/dmux/spec-kit-onboard) |
 | Optimize | Audit and optimize AI governance for context efficiency — token budgets, rule health, interpretability, compression, coherence, and echo detection | `process` | Read+Write | [spec-kit-optimize](https://github.com/sakitA/spec-kit-optimize) |
 | OWASP LLM Threat Model | OWASP Top 10 for LLM Applications 2025 threat analysis on agent artifacts | `code` | Read-only | [spec-kit-threatmodel](https://github.com/NaviaSamal/spec-kit-threatmodel) |
diff --git a/extensions/catalog.community.json b/extensions/catalog.community.json
index 81d4e1f18e..d7503a2a31 100644
--- a/extensions/catalog.community.json
+++ b/extensions/catalog.community.json
@@ -842,6 +842,44 @@
       "created_at": "2026-03-06T00:00:00Z",
       "updated_at": "2026-03-31T00:00:00Z"
     },
+    "fx-to-dotnet": {
+      "name": ".NET Framework to Modern .NET Migration",
+      "id": "fx-to-dotnet",
+      "description": "Orchestrate end-to-end .NET Framework to modern .NET migration across 7 phases, with SDD lifecycle integration.",
+      "author": "RogerBestMsft",
+      "version": "0.8.0",
+      "download_url": "https://github.com/RogerBestMsft/spec-kit-FxToNet/releases/download/v0.8.0/fx-to-dotnet.zip",
+      "repository": "https://github.com/RogerBestMsft/spec-kit-FxToNet",
+      "homepage": "https://github.com/RogerBestMsft/spec-kit-FxToNet",
+      "documentation": "https://github.com/RogerBestMsft/spec-kit-FxToNet/blob/main/README.md",
+      "license": "MIT",
+      "requires": {
+        "speckit_version": ">=0.1.0",
+        "tools": [
+          {
+            "name": "Microsoft.GitHubCopilot.Modernization.Mcp",
+            "required": true
+          }
+        ]
+      },
+      "provides": {
+        "commands": 12,
+        "hooks": 5
+      },
+      "tags": [
+        "dotnet",
+        "migration",
+        "modernization",
+        "framework",
+        "aspnet",
+        "shared-artifact"
+      ],
+      "verified": false,
+      "downloads": 0,
+      "stars": 0,
+      "created_at": "2026-05-06T00:00:00Z",
+      "updated_at": "2026-05-06T00:00:00Z"
+    },
     "github-issues": {
       "name": "GitHub Issues Integration 1",
       "id": "github-issues",