diff --git a/adm/board_form_update.php b/adm/board_form_update.php
index 557a1a2a6..9f9644052 100644
--- a/adm/board_form_update.php
+++ b/adm/board_form_update.php
@@ -28,7 +28,7 @@ $bo_include_head = isset($_POST['bo_include_head']) ? preg_replace(array("#[\\\]
 $bo_include_tail = isset($_POST['bo_include_tail']) ? preg_replace(array("#[\\\]+$#", "#(<\?php|<\?)#i"), "", substr($_POST['bo_include_tail'], 0, 255)) : '';
 
 // 관리자가 자동등록방지를 사용해야 할 경우
-if ($board && ($board['bo_include_head'] !== $bo_include_head || $board['bo_include_tail'] !== $bo_include_tail) && function_exists('get_admin_captcha_by') && get_admin_captcha_by()){
+if ($board && (isset($board['bo_include_head']) && $board['bo_include_head'] !== $bo_include_head || $board['bo_include_tail'] !== $bo_include_tail) && function_exists('get_admin_captcha_by') && get_admin_captcha_by()){
     include_once(G5_CAPTCHA_PATH.'/captcha.lib.php');
 
     if (!chk_captcha()) {
diff --git a/adm/dbupgrade.php b/adm/dbupgrade.php
index 3f6a4be3d..7ac478d40 100644
--- a/adm/dbupgrade.php
+++ b/adm/dbupgrade.php
@@ -197,7 +197,7 @@ if (defined('G5_USE_SHOP') && G5_USE_SHOP) {
 
     $result = sql_query("describe `{$g5['g5_shop_post_log_table']}`");
     while ($row = sql_fetch_array($result)){
-        if( $row['Field'] === 'ol_msg' && $row['Type'] === 'varchar(255)' ){
+        if( isset($row['Field']) && $row['Field'] === 'ol_msg' && $row['Type'] === 'varchar(255)' ){
             sql_query("ALTER TABLE `{$g5['g5_shop_post_log_table']}` MODIFY ol_msg TEXT NOT NULL;", false);
             sql_query("ALTER TABLE `{$g5['g5_shop_post_log_table']}` DROP PRIMARY KEY;", false);
             sql_query("ALTER TABLE `{$g5['g5_shop_post_log_table']}` ADD `log_id` int(11) NOT NULL AUTO_INCREMENT, ADD PRIMARY KEY (`log_id`);", false);
diff --git a/common.php b/common.php
index dd4c2e1af..80171c164 100644
--- a/common.php
+++ b/common.php
@@ -2,7 +2,9 @@
 /*******************************************************************************
 ** 공통 변수, 상수, 코드
 *******************************************************************************/
-error_reporting( E_CORE_ERROR | E_CORE_WARNING | E_COMPILE_ERROR | E_ERROR | E_WARNING | E_PARSE | E_USER_ERROR | E_USER_WARNING );
+// error_reporting( E_CORE_ERROR | E_CORE_WARNING | E_COMPILE_ERROR | E_ERROR | E_WARNING | E_PARSE | E_USER_ERROR | E_USER_WARNING );
+error_reporting(E_ALL);
+ini_set("display_errors", 1);
 
 // 보안설정이나 프레임이 달라도 쿠키가 통하도록 설정
 header('P3P: CP="ALL CURa ADMa DEVa TAIa OUR BUS IND PHY ONL UNI PUR FIN COM NAV INT DEM CNT STA POL HEA PRE LOC OTC"');
diff --git a/lib/common.lib.php b/lib/common.lib.php
index b9fae59b4..1b0acda5e 100644
--- a/lib/common.lib.php
+++ b/lib/common.lib.php
@@ -1511,7 +1511,7 @@ function hsc($str)
 // &nbsp; &amp; &middot; 등을 정상으로 출력
 function html_symbol($str)
 {
-    return preg_replace("/\&([a-z0-9]{1,20}|\#[0-9]{0,3});/i", "&#038;\\1;", $str);
+    return $str ? preg_replace("/\&([a-z0-9]{1,20}|\#[0-9]{0,3});/i", "&#038;\\1;", $str) : "";
 }
 
 
@@ -1609,7 +1609,11 @@ function sql_query($sql, $error=G5_DISPLAY_SQL_ERROR, $link=null)
         if ($error) {
             $result = @mysqli_query($link, $sql) or die("<p>$sql<p>" . mysqli_errno($link) . " : " .  mysqli_error($link) . "<p>error file : {$_SERVER['SCRIPT_NAME']}");
         } else {
-            $result = @mysqli_query($link, $sql);
+            try {
+                $result = @mysqli_query($link, $sql);
+            } catch (Exception $e) {
+                $result = null;
+            }
         }
     } else {
         if ($error) {
@@ -1657,7 +1661,11 @@ function sql_fetch_array($result)
     if( ! $result) return array();
 
     if(function_exists('mysqli_fetch_assoc') && G5_MYSQLI_USE)
-        $row = @mysqli_fetch_assoc($result);
+        try {
+            $row = @mysqli_fetch_assoc($result);
+        } catch (Exception $e) {
+            $row = null;
+        }
     else
         $row = @mysql_fetch_assoc($result);
 
diff --git a/plugin/htmlpurifier/HTMLPurifier.standalone.php b/plugin/htmlpurifier/HTMLPurifier.standalone.php
index 6e9db001f..d889e6af3 100644
--- a/plugin/htmlpurifier/HTMLPurifier.standalone.php
+++ b/plugin/htmlpurifier/HTMLPurifier.standalone.php
@@ -8319,7 +8319,10 @@ class HTMLPurifier_PropertyListIterator extends FilterIterator
 
     /**
      * @return bool
+     *
+     * {@inheritdoc}
      */
+    #[\ReturnTypeWillChange]
     public function accept()
     {
         $key = $this->getInnerIterator()->key();
@@ -8437,7 +8440,10 @@ class HTMLPurifier_StringHash extends ArrayObject
      * Retrieves a value, and logs the access.
      * @param mixed $index
      * @return mixed
+     *
+     * {@inheritdoc}
      */
+    #[\ReturnTypeWillChange]
     public function offsetGet($index)
     {
         $this->accessed[$index] = true;