diff --git a/include/MAPIDefS.h b/include/MAPIDefS.h
index 9e83e2d..73fd58c 100644
--- a/include/MAPIDefS.h
+++ b/include/MAPIDefS.h
@@ -2845,6 +2845,19 @@ DECLARE_MAPI_INTERFACE_(IMAPIProviderShutdown, IUnknown)
 	MAPI_IMAPIPROVIDERSHUTDOWN_METHODS(PURE)
 };
 
+/* WrapCompressedRTFStreamEx ---------------------------------------------- */
+
+/* Flags for WrapCompressedRTFStreamEx */
+
+/****** MAPI_MODIFY					((ULONG) 0x00000001) above */
+/****** STORE_UNCOMPRESSED_RTF		((ULONG) 0x00008000) above */
+#define MAPI_NATIVE_BODY 0x00010000
+
+/* out param type infomation for WrapCompressedRTFStreamEx */
+#define MAPI_NATIVE_BODY_TYPE_RTF 0x00000001
+#define MAPI_NATIVE_BODY_TYPE_HTML 0x00000002
+#define MAPI_NATIVE_BODY_TYPE_PLAINTEXT 0x00000004
+
 #ifdef	__cplusplus
 }		/*	extern "C" */
 #endif
diff --git a/include/MAPIUtil.h b/include/MAPIUtil.h
index fa363d0..9b70cf7 100644
--- a/include/MAPIUtil.h
+++ b/include/MAPIUtil.h
@@ -846,6 +846,44 @@ HrIStorageFromStream (LPUNKNOWN lpUnkIn,
 STDAPI_(SCODE)			ScInitMapiUtil(ULONG ulFlags);
 STDAPI_(VOID)			DeinitMapiUtil(VOID);
 
+// Definitions for WrapCompressedRTFStreamEx in param for WrapCompressedRTFStreamEX
+// https://learn.microsoft.com/en-us/previous-versions/office/developer/office-2007/bb905293(v=office.12)
+struct RTF_WCSINFO
+{
+	ULONG size; // Size of the structure
+	ULONG ulFlags;
+	/****** MAPI_MODIFY ((ULONG) 0x00000001) above */
+	/****** STORE_UNCOMPRESSED_RTF ((ULONG) 0x00008000) above */
+	/****** MAPI_NATIVE_BODY ((ULONG) 0x00010000) mapidefs.h Only used for reading*/
+	ULONG ulInCodePage; // Codepage of the message, used when passing MAPI_NATIVE_BODY, ignored otherwise
+	ULONG ulOutCodePage; // Codepage of the Returned Stream, used when passing MAPI_NATIVE_BODY, ignored otherwise
+};
+
+// out param type information for WrapCompressedRTFStreamEX
+// https://learn.microsoft.com/en-us/previous-versions/office/developer/office-2007/bb905294(v=office.12)
+struct RTF_WCSRETINFO
+{
+	ULONG size; // Size of the structure
+	ULONG ulStreamFlags;
+	/****** MAPI_NATIVE_BODY_TYPE_RTF ((ULONG) 0x00000001) mapidefs.h */
+	/****** MAPI_NATIVE_BODY_TYPE_HTML ((ULONG) 0x00000002) mapidefs.h */
+	/****** MAPI_NATIVE_BODY_TYPE_PLAINTEXT ((ULONG) 0x00000004) mapidefs.h */
+};
+
+STDAPI_(HRESULT)
+WrapCompressedRTFStreamEx(
+	LPSTREAM pCompressedRTFStream,
+	const RTF_WCSINFO* pWCSInfo,
+	LPSTREAM* ppUncompressedRTFStream,
+	RTF_WCSRETINFO* pRetInfo);
+
+_Check_return_ STDAPI OpenStreamOnFileW(
+	_In_ LPALLOCATEBUFFER lpAllocateBuffer,
+	_In_ LPFREEBUFFER lpFreeBuffer,
+	ULONG ulFlags,
+	_In_z_ LPCWSTR lpszFileName,
+	_In_opt_z_ LPCWSTR lpszPrefix,
+	_Out_ LPSTREAM FAR* lppStream);
 
 /*
  *	Entry point names.
diff --git a/library/mapiStubLibrary.cpp b/library/mapiStubLibrary.cpp
index 8d95fbf..a228a01 100644
--- a/library/mapiStubLibrary.cpp
+++ b/library/mapiStubLibrary.cpp
@@ -53,8 +53,6 @@
 
 struct MAPIOFFLINE_CREATEINFO;
 struct IMAPIOfflineMgr;
-struct RTF_WCSINFO;
-struct RTF_WCSRETINFO;
 
 #define LINKAGE_EXTERN_C extern "C"
 #define LINKAGE_NO_EXTERN_C /* */
@@ -2512,8 +2510,8 @@ DEFINE_STUB_FUNCTION_6(
 	LPALLOCATEBUFFER,
 	LPFREEBUFFER,
 	ULONG,
-	LPWSTR,
-	LPWSTR,
+	LPCWSTR,
+	LPCWSTR,
 	LPSTREAM FAR*,
 	MAPI_E_CALL_FAILED)