diff --git a/bbs/login_check.php b/bbs/login_check.php
index 9b1a8c42a..18d31e21d 100644
--- a/bbs/login_check.php
+++ b/bbs/login_check.php
@@ -72,7 +72,7 @@ if ($auto_login) {
     // 3.27
     // 자동로그인 ---------------------------
     // 쿠키 한달간 저장
-    $key = md5($_SERVER['SERVER_ADDR'] . $_SERVER['REMOTE_ADDR'] . $_SERVER['HTTP_USER_AGENT'] . $mb['mb_password']);
+    $key = md5($_SERVER['SERVER_ADDR'] . $_SERVER['SERVER_SOFTWARE'] . $_SERVER['HTTP_USER_AGENT'] . $mb['mb_password']);
     set_cookie('ck_mb_id', $mb['mb_id'], 86400 * 31);
     set_cookie('ck_auto', $key, 86400 * 31);
     // 자동로그인 end ---------------------------
diff --git a/common.php b/common.php
index a4ca21717..a5477de65 100644
--- a/common.php
+++ b/common.php
@@ -374,7 +374,7 @@ if ($_SESSION['ss_mb_id']) { // 로그인중이라면
             $sql = " select mb_password, mb_intercept_date, mb_leave_date, mb_email_certify from {$g5['member_table']} where mb_id = '{$tmp_mb_id}' ";
             $row = sql_fetch($sql);
             if($row['mb_password']){
-                $key = md5($_SERVER['SERVER_ADDR'] . $_SERVER['REMOTE_ADDR'] . $_SERVER['HTTP_USER_AGENT'] . $row['mb_password']);
+                $key = md5($_SERVER['SERVER_ADDR'] . $_SERVER['SERVER_SOFTWARE'] . $_SERVER['HTTP_USER_AGENT'] . $row['mb_password']);
                 // 쿠키에 저장된 키와 같다면
                 $tmp_key = get_cookie('ck_auto');
                 if ($tmp_key === $key && $tmp_key) {
diff --git a/config.php b/config.php
index 56ef66c40..3d3650376 100644
--- a/config.php
+++ b/config.php
@@ -5,8 +5,8 @@
 ********************/
 
 define('G5_VERSION', '그누보드5');
-define('G5_GNUBOARD_VER', '5.3.1.5');
-define('G5_YOUNGCART_VER', '5.3.1.5');
+define('G5_GNUBOARD_VER', '5.3.1.6');
+define('G5_YOUNGCART_VER', '5.3.1.6');
 
 // 이 상수가 정의되지 않으면 각각의 개별 페이지는 별도로 실행될 수 없음
 define('_GNUBOARD_', true);