diff --git a/src/userfunc.c b/src/userfunc.c
index d5dd36989..c3b2a2535 100644
--- a/src/userfunc.c
+++ b/src/userfunc.c
@@ -3060,7 +3060,11 @@ call_user_func(
 	clear_tv(rettv);
 	rettv->v_type = VAR_NUMBER;
 	rettv->vval.v_number = -1;
-	retval = FCERR_FAILED;
+
+	// In corner cases returning a "failed" value is not backwards
+	// compatible.  Only do this for Vim9 script.
+	if (in_vim9script())
+	    retval = FCERR_FAILED;
     }
 
 #ifdef FEAT_PROFILE
diff --git a/src/version.c b/src/version.c
index 20df49098..41822fdf4 100644
--- a/src/version.c
+++ b/src/version.c
@@ -695,6 +695,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    1321,
 /**/
     1320,
 /**/