diff --git a/main/inc/lib/banner.lib.php b/main/inc/lib/banner.lib.php
index 829254fe64..dca8c0b673 100755
--- a/main/inc/lib/banner.lib.php
+++ b/main/inc/lib/banner.lib.php
@@ -730,7 +730,7 @@ function getOnlineUsersCount()
     $number = 0;
     $cacheAvailable = api_get_configuration_value('apc');
     if (!empty($cacheAvailable)) {
-        $apcVar = api_get_configuration_value('apc_refix') . 'my_campus_whoisonline_count_simple';
+        $apcVar = api_get_configuration_value('apc_prefix') . 'my_campus_whoisonline_count_simple';
         if (apcu_exists($apcVar)) {
             $number = apcu_fetch($apcVar);
         } else {
@@ -756,7 +756,7 @@ function getOnlineUsersInCourseCount($userId, $_course)
     $numberOnlineInCourse = 0;
     if (!empty($_course['id'])) {
         if (!empty($cacheAvailable)) {
-            $apcVar = api_get_configuration_value('apc_refix') . 'my_campus_whoisonline_count_simple_' . $_course['id'];
+            $apcVar = api_get_configuration_value('apc_prefix') . 'my_campus_whoisonline_count_simple_' . $_course['id'];
             if (apcu_exists($apcVar)) {
                 $numberOnlineInCourse = apcu_fetch($apcVar);
             } else {
diff --git a/main/inc/lib/message.lib.php b/main/inc/lib/message.lib.php
index ac2533619c..8c0c2199b0 100755
--- a/main/inc/lib/message.lib.php
+++ b/main/inc/lib/message.lib.php
@@ -29,7 +29,7 @@ class MessageManager
         if (!isset($count)) {
             $cacheAvailable = api_get_configuration_value('apc');
             if (!empty($cacheAvailable)) {
-                $var = api_get_configuration_value('apc_refix') . 'social_messages_unread_u_' . $userId;
+                $var = api_get_configuration_value('apc_prefix') . 'social_messages_unread_u_' . $userId;
                 if (apcu_exists($var)) {
                     $count = apcu_fetch($var);
                 } else {
diff --git a/main/inc/lib/tracking.lib.php b/main/inc/lib/tracking.lib.php
index 437c1391f7..e00245060a 100755
--- a/main/inc/lib/tracking.lib.php
+++ b/main/inc/lib/tracking.lib.php
@@ -1702,7 +1702,7 @@ class Tracking
         if (!empty($cacheAvailable)) {
             $apc = apcu_cache_info(true);
             $apc_end = $apc['start_time'] + $apc['ttl'];
-            $apc_var = api_get_configuration_value('apc_refix') . 'course_access_' . $courseId . '_' . $session_id . '_' . strtotime($roundedStart) . '_' . strtotime($roundedStop);
+            $apc_var = api_get_configuration_value('apc_prefix') . 'course_access_' . $courseId . '_' . $session_id . '_' . strtotime($roundedStart) . '_' . strtotime($roundedStop);
             if (apcu_exists($apc_var) && (time() < $apc_end) &&
                 apcu_fetch($apc_var) > 0
             ) {