diff --git a/instructions/aspnet-rest-apis.instructions.md b/instructions/aspnet-rest-apis.instructions.md
index ed68c03a..612d3e80 100644
--- a/instructions/aspnet-rest-apis.instructions.md
+++ b/instructions/aspnet-rest-apis.instructions.md
@@ -66,7 +66,7 @@ applyTo: '**/*.cs, **/*.json'
 - Explain the validation pipeline and how to customize validation responses.
 - Demonstrate a global exception handling strategy using middleware.
 - Show how to create consistent error responses across the API.
-- Explain problem details (RFC 7807) implementation for standardized error responses.
+- Explain problem details (RFC 9457) implementation for standardized error responses.
 
 ## API Versioning and Documentation
 
diff --git a/instructions/csharp-ja.instructions.md b/instructions/csharp-ja.instructions.md
index 92594e49..dea3b81f 100644
--- a/instructions/csharp-ja.instructions.md
+++ b/instructions/csharp-ja.instructions.md
@@ -67,7 +67,7 @@ applyTo: '**/*.cs'
 - 検証パイプラインと、検証応答のカスタマイズ方法を説明します。
 - ミドルウェアを用いたグローバル例外処理戦略を示します。
 - API 全体で一貫したエラー応答を作成する方法を示します。
-- 標準化されたエラー応答のための Problem Details（RFC 7807）の実装を説明します。
+- 標準化されたエラー応答のための Problem Details（RFC 9457）の実装を説明します。
 
 ## API のバージョニングとドキュメント
 
diff --git a/instructions/csharp.instructions.md b/instructions/csharp.instructions.md
index 8d6f4c20..16355d2c 100644
--- a/instructions/csharp.instructions.md
+++ b/instructions/csharp.instructions.md
@@ -67,7 +67,7 @@ applyTo: '**/*.cs'
 - Explain the validation pipeline and how to customize validation responses.
 - Demonstrate a global exception handling strategy using middleware.
 - Show how to create consistent error responses across the API.
-- Explain problem details (RFC 7807) implementation for standardized error responses.
+- Explain problem details (RFC 9457) implementation for standardized error responses.
 
 ## API Versioning and Documentation