diff --git a/src/structs.h b/src/structs.h
index 9addf1a..ce9dfbc 100644
--- a/src/structs.h
+++ b/src/structs.h
@@ -67,6 +67,8 @@
 typedef struct VimMenu vimmenu_T;
 #endif
 
+// maximum value for sc_version
+#define SCRIPT_VERSION_MAX 4
 // value for sc_version in a Vim9 script file
 #define SCRIPT_VERSION_VIM9 999999