diff --git a/plugins/password/composer.json b/plugins/password/composer.json
index 028ef373a..1e7fb6f84 100644
--- a/plugins/password/composer.json
+++ b/plugins/password/composer.json
@@ -3,7 +3,7 @@
     "type": "roundcube-plugin",
     "description": "Password Change for Roundcube. Plugin adds a possibility to change user password using many methods (drivers) via Settings/Password tab.",
     "license": "GPLv3+",
-    "version": "5.0",
+    "version": "5.1",
     "authors": [
         {
             "name": "Aleksander Machniak",
diff --git a/plugins/password/drivers/sql.php b/plugins/password/drivers/sql.php
index ca7e0d983..d68edda02 100644
--- a/plugins/password/drivers/sql.php
+++ b/plugins/password/drivers/sql.php
@@ -5,7 +5,7 @@
  *
  * Driver for passwords stored in SQL database
  *
- * @version 2.0
+ * @version 2.1
  * @author Aleksander Machniak <alec@alec.pl>
  *
  * Copyright (C) The Roundcube Dev Team
@@ -23,9 +23,16 @@
  * You should have received a copy of the GNU General Public License
  * along with this program. If not, see http://www.gnu.org/licenses/.
  */
-
 class rcube_sql_password
 {
+    /**
+     * Update current user password
+     *
+     * @param string $curpass Current password
+     * @param string $passwd  New password
+     *
+     * @return int Result
+     */
     function save($curpass, $passwd)
     {
         $rcmail = rcmail::get_instance();
@@ -159,11 +166,11 @@ class rcube_sql_password
                 }
             }
             else {
-                // This is the good case: 1 row updated
-                if ($db->affected_rows($res) == 1)
+                // Note: Don't be tempted to check affected_rows = 1. For some queries
+                // (e.g. INSERT ... ON DUPLICATE KEY UPDATE) the result can be 2.
+                if ($db->affected_rows($res) > 0) {
                     return PASSWORD_SUCCESS;
-                // @TODO: Some queries don't affect any rows
-                // Should we assume a success if there was no error?
+                }
             }
         }
 
@@ -172,6 +179,10 @@ class rcube_sql_password
 
     /**
      * Parse DSN string and replace host variables
+     *
+     * @param string $dsn DSN string
+     *
+     * @return string DSN string
      */
     protected static function parse_dsn($dsn)
     {