diff --git a/adm/mail_delete.php b/adm/mail_delete.php
index a351bd879..7d2999cfa 100644
--- a/adm/mail_delete.php
+++ b/adm/mail_delete.php
@@ -10,10 +10,10 @@ check_admin_token();
 
 $post_count_chk = (isset($_POST['chk']) && is_array($_POST['chk'])) ? count($_POST['chk']) : 0;
 
-if(!$count)
+if(! $post_count_chk)
     alert('삭제할 메일목록을 1개이상 선택해 주세요.');
 
-for($i=0; $i<$count; $i++) {
+for($i=0; $i<$post_count_chk; $i++) {
     $ma_id = isset($_POST['chk'][$i]) ? (int) $_POST['chk'][$i] : 0;
 
     $sql = " delete from {$g5['mail_table']} where ma_id = '$ma_id' ";
diff --git a/config.php b/config.php
index f8fcb5f4b..181913d7e 100644
--- a/config.php
+++ b/config.php
@@ -5,8 +5,8 @@
 ********************/
 
 define('G5_VERSION', '그누보드5');
-define('G5_GNUBOARD_VER', '5.4.4.9');
-define('G5_YOUNGCART_VER', '5.4.4.9.1');
+define('G5_GNUBOARD_VER', '5.4.5');
+define('G5_YOUNGCART_VER', '5.4.5');
 
 // 이 상수가 정의되지 않으면 각각의 개별 페이지는 별도로 실행될 수 없음
 define('_GNUBOARD_', true);
diff --git a/install/install_db.php b/install/install_db.php
index 757e38040..969703d70 100644
--- a/install/install_db.php
+++ b/install/install_db.php
@@ -59,6 +59,7 @@ if (!$dblink) {
     exit;
 }
 
+$g5['connect_db'] = $dblink;
 $select_db = sql_select_db($mysql_db, $dblink);
 if (!$select_db) {
 ?>
@@ -225,6 +226,7 @@ if($g5_install || !$result) {
                      mb_level = '10',
                      mb_mailling = '1',
                      mb_open = '1',
+                     mb_nick_date = '".G5_TIME_YMDHIS."',
                      mb_email_certify = '".G5_TIME_YMDHIS."',
                      mb_datetime = '".G5_TIME_YMDHIS."',
                      mb_ip = '{$_SERVER['REMOTE_ADDR']}'
diff --git a/lib/Hook/hook.extends.class.php b/lib/Hook/hook.extends.class.php
index 4ebdb4a89..bf5bc03e2 100644
--- a/lib/Hook/hook.extends.class.php
+++ b/lib/Hook/hook.extends.class.php
@@ -130,10 +130,11 @@ Class GML_Hook extends Hook {
 
         if (isset($that->callback_filters[$tag]) && isset($that->callback_filters[$tag][$priority]) ) {
             
-            $found_key = array_search($func, array_column($that->callback_filters[$tag][$priority], 'function'));
-
-            if( $found_key !== false ){
-                unset($that->callback_filters[$tag][$priority][$found_key]);
+            foreach((array) $that->callback_filters[$tag][$priority] as $key=>$value){
+                if(isset($value['function']) && $value['function'] === $func) {
+                    unset($that->callback_filters[$tag][$priority][$key]);
+                    $is_remove = true;
+                }
             }
         }
 
@@ -148,10 +149,11 @@ Class GML_Hook extends Hook {
 
         if (isset($that->callbacks[$tag]) && isset($that->callbacks[$tag][$priority]) ) {
             
-            $found_key = array_search($func, array_column($that->callbacks[$tag][$priority], 'function'));
-
-            if( $found_key !== false ){
-                unset($that->callbacks[$tag][$priority][$found_key]);
+            foreach((array) $that->callbacks[$tag][$priority] as $key=>$value){
+                if(isset($value['function']) && $value['function'] === $func) {
+                    unset($that->callbacks[$tag][$priority][$key]);
+                    $is_remove = true;
+                }
             }
         }
 
diff --git a/lib/cache.lib.php b/lib/cache.lib.php
index 5e6c7c6c7..25790dd92 100644
--- a/lib/cache.lib.php
+++ b/lib/cache.lib.php
@@ -8,6 +8,8 @@ function get_cachemanage_instance(){
     static $instance = null;
     
     if( ! (defined('G5_USE_CACHE') && G5_USE_CACHE) ) return $instance;
+    
+    $instance = run_replace('get_cachemanage_instance', $instance);
 
     if( $instance === null ){
         $options = array(
@@ -48,14 +50,22 @@ function g5_latest_cache_data($bo_table, $cache_list=array(), $find_wr_id=0){
 function g5_set_cache($key, $save_data, $ttl = null){
 
     if( $cache = get_cachemanage_instance() ){
-        $cache->save($key, $save_data, $ttl);
+        run_event('g5_set_cache_event', $cache, $key, $save_data, $ttl);
+        
+        if( (is_object($cache) && get_class($cache) === 'FileCache') ){
+            $cache->save($key, $save_data, $ttl);
+        }
     }
 }
 
 function g5_get_cache($key, $expired_time=0){
 
     if( $cache = get_cachemanage_instance() ){
-        return $cache->get($key, $expired_time);
+        if( (is_object($cache) && get_class($cache) === 'FileCache') ){
+            return $cache->get($key, $expired_time);
+        }
+
+        return run_replace('g5_get_cache_replace', false, $cache, $key, $expired_time);
     }
     
     return false;
@@ -82,13 +92,21 @@ function g5_delete_all_cache(){
 }
 
 function g5_delete_cache_by_prefix($key){
-    $files = glob(G5_DATA_PATH.'/cache/'.$key.'*');
 
-    foreach( (array) $files as $filename){
-        if(empty($filename)) continue;
+    $cache = get_cachemanage_instance();
+    $files = null;
 
-        unlink($filename);
+    if( (is_object($instance) && get_class($instance) === 'FileCache') ) {
+        $files = glob(G5_DATA_PATH.'/cache/'.$key.'*');
+
+        foreach( (array) $files as $filename){
+            if(empty($filename)) continue;
+
+            unlink($filename);
+        }
     }
 
+    $files = run_replace('g5_delete_cache_by_prefix', $files, $key);
+
     return ($files) ? true : false;
 }
\ No newline at end of file