diff --git a/include/WinStd/Common.h b/include/WinStd/Common.h
index 92e721a1..9a377960 100644
--- a/include/WinStd/Common.h
+++ b/include/WinStd/Common.h
@@ -252,6 +252,7 @@ inline SIZE_T SIZETAdd(SIZE_T a, SIZE_T b)
 ///
 /// \returns Number of characters in result.
 ///
+[[deprecated("Behavior of this function changed from append to assign. Please, review call usage.")]]
 template<class _Traits, class _Ax>
 static int vsprintf(_Inout_ std::basic_string<char, _Traits, _Ax> &str, _In_z_ _Printf_format_string_ const char *format, _In_ va_list arg)
 {
@@ -290,6 +291,7 @@ static int vsprintf(_Inout_ std::basic_string<char, _Traits, _Ax> &str, _In_z_ _
 ///
 /// \returns Number of characters in result.
 ///
+[[deprecated("Behavior of this function changed from append to assign. Please, review call usage.")]]
 template<class _Traits, class _Ax>
 static int vsprintf(_Inout_ std::basic_string<wchar_t, _Traits, _Ax> &str, _In_z_ _Printf_format_string_ const wchar_t *format, _In_ va_list arg)
 {