diff --git a/etc/inc/upgrade_config.inc b/etc/inc/upgrade_config.inc
index f111ef6b5a..6c8331b008 100644
--- a/etc/inc/upgrade_config.inc
+++ b/etc/inc/upgrade_config.inc
@@ -2602,6 +2602,7 @@ function upgrade_076_to_077() {
 }
 
 function upgrade_077_to_078() {
+	global $config;
 	if (is_array($config['pptpd']) && is_array($config['pptpd']['radius'])
 		&& !is_array($config['pptpd']['radius']['server'])) {
 		$radarr = array();