From 0961139ea46c66990178fb2d5097515ea1bc6331 Mon Sep 17 00:00:00 2001
From: caoyanyi <caoyanyi@easycorp.ltd>
Date: Wed, 23 Mar 2022 09:14:27 +0800
Subject: [PATCH] * Fix bug #18017.

---
 module/user/model.php | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/module/user/model.php b/module/user/model.php
index eadbe7e435..4ad6e0849c 100644
--- a/module/user/model.php
+++ b/module/user/model.php
@@ -126,7 +126,7 @@ class userModel extends model
             }
             else
             {
-                $firstLetter = ucfirst(substr($user->account, 0, 1)) . ':';
+                $firstLetter = ucfirst(mb_substr($user->account, 0, 1)) . ':';
                 if(strpos($params, 'noletter') !== false or !empty($this->config->isINT)) $firstLetter = '';
                 $users[$account] =  $firstLetter . (($user->deleted and strpos($params, 'realname') === false) ? $user->account : ($user->realname ? $user->realname : $user->account));
             }