diff --git a/Win32/Win32App.cpp b/Win32/Win32App.cpp
index 9eae7a95..fc61a8ac 100644
--- a/Win32/Win32App.cpp
+++ b/Win32/Win32App.cpp
@@ -348,6 +348,9 @@ namespace win32
 						}
 					}
 				}
+#if (__cplusplus >= 201703L) // C++ 17 or higher
+				[[fallthrough]];
+#endif
 			}
 			case WM_TRAYICON:
 			{