diff --git a/src/userfunc.c b/src/userfunc.c
index ae3e202..f612160 100644
--- a/src/userfunc.c
+++ b/src/userfunc.c
@@ -3995,7 +3995,8 @@
     {
 	if (!vim9_local)
 	{
-	    if (vim9script && lead == 2 && !ASCII_ISUPPER(*lv.ll_name))
+	    if (vim9script && lead == 2 && !ASCII_ISUPPER(*lv.ll_name)
+						   && current_script_is_vim9())
 	    {
 		semsg(_(e_function_name_must_start_with_capital_str), start);
 		goto theend;