diff --git a/src/mibew/libs/classes/Mibew/Controller/Chat/User/MailController.php b/src/mibew/libs/classes/Mibew/Controller/Chat/User/MailController.php
index 34501976..7c1e4879 100644
--- a/src/mibew/libs/classes/Mibew/Controller/Chat/User/MailController.php
+++ b/src/mibew/libs/classes/Mibew/Controller/Chat/User/MailController.php
@@ -39,8 +39,6 @@ class MailController extends AbstractController
      */
     public function indexAction(Request $request)
     {
-        global $mibew_mailbox;
-
         $page = array(
             'errors' => array(),
         );
@@ -102,7 +100,7 @@ class MailController extends AbstractController
             true
         );
 
-        mibew_mail($email, $mibew_mailbox, $subject, $body);
+        mibew_mail($email, MIBEW_MAILBOX, $subject, $body);
 
         $page = array_merge_recursive($page, setup_logo($group));
 
diff --git a/src/mibew/libs/common/constants.php b/src/mibew/libs/common/constants.php
index e645486f..c4eedb3d 100644
--- a/src/mibew/libs/common/constants.php
+++ b/src/mibew/libs/common/constants.php
@@ -55,3 +55,8 @@ define('VISITOR_COOKIE_NAME', 'MIBEW_VisitorID');
  */
 define('USERID_COOKIE_NAME', 'MIBEW_UserID');
 define('USERNAME_COOKIE_NAME', 'MIBEW_Data');
+
+/**
+ * Mailbox of the current installation
+ */
+define('MIBEW_MAILBOX', $mibew_mailbox);
diff --git a/src/mibew/libs/notify.php b/src/mibew/libs/notify.php
index fbb30187..1eb9fa95 100644
--- a/src/mibew/libs/notify.php
+++ b/src/mibew/libs/notify.php
@@ -17,9 +17,7 @@
 
 function mibew_mail($to_addr, $reply_to, $subject, $body)
 {
-    global $mibew_mailbox;
-
-    $headers = "From: $mibew_mailbox\r\n"
+    $headers = "From: " . MIBEW_MAILBOX . "\r\n"
         . "Reply-To: " . $reply_to . "\r\n"
         . "Content-Type: text/plain; charset=utf-8\r\n"
         . 'X-Mailer: PHP/' . phpversion();
@@ -29,7 +27,7 @@ function mibew_mail($to_addr, $reply_to, $subject, $body)
     $body = preg_replace("/\n/", "\r\n", $body);
 
     $old_from = ini_get('sendmail_from');
-    @ini_set('sendmail_from', $mibew_mailbox);
+    @ini_set('sendmail_from', MIBEW_MAILBOX);
     @mail(
         $to_addr,
         $real_subject,