diff -u -r SNMP_Session-1.13.orig/lib/SNMP_Session.pm SNMP_Session-1.13/lib/SNMP_Session.pm
--- SNMP_Session-1.13.orig/lib/SNMP_Session.pm	2023-06-05 11:48:19.304310300 +0200
+++ SNMP_Session-1.13/lib/SNMP_Session.pm	2023-06-05 11:48:48.422475999 +0200
@@ -622,7 +622,7 @@
        $local_hostname,$ipv4only) = @_;
     my($remote_addr,$socket,$sockfamily);
 
-    $ipv4only = 1 unless defined $ipv4only;
+    $ipv4only = 1 if defined $ipv4only;
     $sockfamily = AF_INET;
 
     $community = 'public' unless defined $community;