diff --git a/documentation/optimization.html b/documentation/optimization.html
index b9cfbc9a77..28019dfcf7 100755
--- a/documentation/optimization.html
+++ b/documentation/optimization.html
@@ -171,9 +171,9 @@ An optional additional caching mechanism you may use is the realpath_cache_size
     See <a href="http://php.net/manual/en/ini.core.php">the PHP documentation</a>
     for more details.
 <br />
-<br />
+    <br />
     <h3>APC</h3>
-If you prefer using <a href="http://php.net/manual/en/book.apc.php">APC</a>,
+    If you prefer using <a href="http://php.net/manual/en/book.apc.php">APC</a>,
     you can use the same kind of trick as above, just changing the code a little:
 <pre>
     $xc = function_exists('apc_exists');
@@ -209,6 +209,76 @@ If you prefer using <a href="http://php.net/manual/en/book.apc.php">APC</a>,
         }
      ...
 </pre>
+<br />
+<br />
+    <h3>APCu</h3>
+In PHP 5.5 and above, APC is rendered practically obsolete by the presence of ZendOPCache by default.
+    However, APC does not cover the "user cache", like the caching of specific variables in memory.
+    Considering this, you can <a href="http://php.net/manual/en/book.apcu.php">APCu</a> to add the same level of variable caching as described above, just changing the code a little:
+<pre>
+function return_notification_menu()
+{
+    $_course = api_get_course_info();
+    $course_id = 0;
+    if (!empty($_course)) {
+        $course_id  = $_course['code'];
+    }
+
+    $user_id = api_get_user_id();
+
+    $html = '';
+    $cacheEnabled = function_exists('apcu_exists');
+
+    if ((api_get_setting('showonline', 'world') == 'true' && !$user_id) ||
+        (api_get_setting('showonline', 'users') == 'true' && $user_id) ||
+        (api_get_setting('showonline', 'course') == 'true' && $user_id && $course_id)
+    ) {
+
+        if ($cacheEnabled) {
+            $apc = apcu_cache_info(null,true);
+            $apc_end = $apc['start_time']+$apc['ttl'];
+            if (apcu_exists('my_campus_whoisonline_count_simple') AND (time() < $apc_end) AND apcu_fetch('my_campus_whoisonline_count_simple') > 0 ) {
+                $number = apcu_fetch('my_campus_whoisonline_count_simple');
+            } else {
+                $number = who_is_online_count(api_get_setting('time_limit_whosonline'));
+                apcu_clear_cache();
+                apcu_store('my_campus_whoisonline_count_simple',$number,15);
+            }
+        } else {
+            $number = who_is_online_count(api_get_setting('time_limit_whosonline'));
+        }
+
+        $number_online_in_course = 0;
+        if (!empty($_course['id'])) {
+            if ($cacheEnabled) {
+                $apc = apcu_cache_info(null,true);
+                $apc_end = $apc['start_time']+$apc['ttl'];
+                if (apcu_exists('my_campus_whoisonline_count_simple_'.$_course['id']) AND (time() < $apc_end) AND apcu_fetch('my_campus_whoisonline_count_simple_'.$_course['id']) > 0) {
+                    $number_online_in_course = apcu_fetch('my_campus_whoisonline_count_simple_'.$_course['id']);
+                } else {
+                    $number_online_in_course = who_is_online_in_this_course_count($user_id, api_get_setting('time_limit_whosonline'), $_course['id']);
+                    apcu_store('my_campus_whoisonline_count_simple_'.$_course['id'],$number_online_in_course,15);
+                }
+            } else {
+                $number_online_in_course = who_is_online_in_this_course_count(
+                    $user_id,
+                    api_get_setting('time_limit_whosonline'),
+                    $_course['id']
+                );
+            }
+        }
+
+        // Display the who's online of the platform
+        if ($number) {
+            if ((api_get_setting('showonline', 'world') == 'true' && !$user_id) ||
+                (api_get_setting('showonline', 'users') == 'true' && $user_id)
+            ) {
+                $html .= '<li><a href="'.api_get_path(WEB_PATH).'whoisonline.php" target="_self" title="'.get_lang('UsersOnline').'" >'.
+                            Display::return_icon('user.png', get_lang('UsersOnline'), array(), ICON_SIZE_TINY).' '.$number.'</a></li>';
+            }
+        }
+     ...
+</pre>
 <br />
     <h3>Memcached</h3>
 If you use php5-memcached (different set of functions than php5-memcache!),
diff --git a/main/inc/lib/banner.lib.php b/main/inc/lib/banner.lib.php
index ef80411b8b..9ab528f4d1 100755
--- a/main/inc/lib/banner.lib.php
+++ b/main/inc/lib/banner.lib.php
@@ -239,20 +239,45 @@ function return_notification_menu()
     $user_id = api_get_user_id();
 
     $html = '';
-
+    $cacheEnabled = function_exists('apcu_exists');
+    
     if ((api_get_setting('showonline', 'world') == 'true' && !$user_id) ||
         (api_get_setting('showonline', 'users') == 'true' && $user_id) ||
         (api_get_setting('showonline', 'course') == 'true' && $user_id && $course_id)
     ) {
-        $number = who_is_online_count(api_get_setting('time_limit_whosonline'));
+
+        if ($cacheEnabled) {
+            $apc = apcu_cache_info(null,true);
+            $apc_end = $apc['start_time']+$apc['ttl'];
+            if (apcu_exists('my_campus_whoisonline_count_simple') AND (time() < $apc_end) AND apcu_fetch('my_campus_whoisonline_count_simple') > 0 ) {
+                $number = apcu_fetch('my_campus_whoisonline_count_simple');
+            } else {
+                $number = who_is_online_count(api_get_setting('time_limit_whosonline'));
+                apcu_clear_cache();
+                apcu_store('my_campus_whoisonline_count_simple',$number,15);
+            }
+        } else {
+            $number = who_is_online_count(api_get_setting('time_limit_whosonline'));
+        }
 
         $number_online_in_course = 0;
         if (!empty($_course['id'])) {
-            $number_online_in_course = who_is_online_in_this_course_count(
-                $user_id,
-                api_get_setting('time_limit_whosonline'),
-                $_course['id']
-            );
+            if ($cacheEnabled) {
+                $apc = apcu_cache_info(null,true);
+                $apc_end = $apc['start_time']+$apc['ttl'];
+                if (apcu_exists('my_campus_whoisonline_count_simple_'.$_course['id']) AND (time() < $apc_end) AND apcu_fetch('my_campus_whoisonline_count_simple_'.$_course['id']) > 0) {
+                    $number_online_in_course = apcu_fetch('my_campus_whoisonline_count_simple_'.$_course['id']);
+                } else {
+                    $number_online_in_course = who_is_online_in_this_course_count($user_id, api_get_setting('time_limit_whosonline'), $_course['id']);
+                    apcu_store('my_campus_whoisonline_count_simple_'.$_course['id'],$number_online_in_course,15);
+                }
+            } else {
+                $number_online_in_course = who_is_online_in_this_course_count(
+                    $user_id,
+                    api_get_setting('time_limit_whosonline'),
+                    $_course['id']
+                );
+            }
         }
 
         // Display the who's online of the platform