Single session Admin can be set in the misc settings

system/autoload/Admin.php

@@ -149,7 +149,14 @@ class Admin
 
     public static function validateToken($aid, $cookieToken)
     {
+        global $config;
         $query =  ORM::for_table('tbl_users')->select('login_token')->findOne($aid);
+        if($config['single_session'] != 'yes'){
+            return true; // For multi-session, any token is valid
+        }
+        if(empty($query)){
+            return true;
+        }
         return $query->login_token === sha1($cookieToken);
     }
 }

system/lan/english.json

@@ -849,5 +849,8 @@
     "Ask_Telegram_Community": "Ask Telegram Community",
     "Transaction_History_List": "Transaction History List",
     "Login_as_Customer": "Login as Customer",
-    "info": "info"
+    "info": "info",
+    "Registration_code": "Registration code",
+    "Admin_can_only_have_single_session_login__it_will_logout_another_session": "Admin can only have single session login, it will logout another session",
+    "Single_session_Admin": "Single session Admin"
 }

ui/ui/app-miscellaneous.tpl

@@ -36,6 +36,21 @@
                                 minutes')}
                             </p>
                         </div>
+                        <div class="form-group">
+                            <label class="col-md-2 control-label">{Lang::T('Single session Admin')}</label>
+                            <div class="col-md-6">
+                                <select name="single_session" id="single_session" class="form-control">
+                                    <option value="no">
+                                        {Lang::T('No')}</option>
+                                    <option value="yes" {if $_c['single_session']=='yes' }selected="selected" {/if}>
+                                        {Lang::T('Yes')}
+                                    </option>
+                                </select>
+                            </div>
+                            <p class="help-block col-md-4">
+                                {Lang::T('Admin can only have single session login, it will logout another session')}
+                            </p>
+                        </div>
                         <div class="form-group">
                             <label class="col-md-2 control-label">{Lang::T('New Version Notification')}</label>
                             <div class="col-md-6">