diff --git a/lib/adodb/adodb-iterator.inc.php b/lib/adodb/adodb-iterator.inc.php
deleted file mode 100644
index b5c9133d87b..00000000000
--- a/lib/adodb/adodb-iterator.inc.php
+++ /dev/null
@@ -1,26 +0,0 @@
-<?php
-
-/*
-  @version   v5.21.0  2021-02-27
-  @copyright (c) 2000-2013 John Lim (jlim#natsoft.com). All rights reserved.
-  @copyright (c) 2014      Damien Regad, Mark Newnham and the ADOdb community
-  Released under both BSD license and Lesser GPL library license.
-  Whenever there is any discrepancy between the two licenses,
-  the BSD license will take precedence.
-
-  Set tabs to 4.
-
-  Declares the ADODB Base Class for PHP5 "ADODB_BASE_RS", and supports iteration with
-  the ADODB_Iterator class.
-
-  		$rs = $db->Execute("select * from adoxyz");
-		foreach($rs as $k => $v) {
-			echo $k; print_r($v); echo "<br>";
-		}
-
-
-	Iterator code based on http://cvs.php.net/cvs.php/php-src/ext/spl/examples/cachingiterator.inc?login=2
-
-
-	Moved to adodb.inc.php to improve performance.
- */
diff --git a/lib/adodb/adodb-php4.inc.php b/lib/adodb/adodb-php4.inc.php
deleted file mode 100644
index eea5818b28f..00000000000
--- a/lib/adodb/adodb-php4.inc.php
+++ /dev/null
@@ -1,16 +0,0 @@
-<?php
-
-/*
-  @version   v5.21.0  2021-02-27
-  @copyright (c) 2000-2013 John Lim (jlim#natsoft.com). All rights reserved.
-  @copyright (c) 2014      Damien Regad, Mark Newnham and the ADOdb community
-  Released under both BSD license and Lesser GPL library license.
-  Whenever there is any discrepancy between the two licenses,
-  the BSD license will take precedence.
-
-  Set tabs to 4.
-*/
-
-
-class ADODB_BASE_RS {
-}
diff --git a/lib/adodb/lang/adodb-en.inc.php b/lib/adodb/lang/adodb-en.inc.php
index 05828554c35..74c4ea021b3 100644
--- a/lib/adodb/lang/adodb-en.inc.php
+++ b/lib/adodb/lang/adodb-en.inc.php
@@ -1,4 +1,23 @@
 <?php
+/**
+ * English language strings.
+ *
+ * This file is part of ADOdb, a Database Abstraction Layer library for PHP.
+ *
+ * @package ADOdb
+ * @link https://adodb.org Project's web site and documentation
+ * @link https://github.com/ADOdb/ADOdb Source code and issue tracker
+ *
+ * The ADOdb Library is dual-licensed, released under both the BSD 3-Clause
+ * and the GNU Lesser General Public Licence (LGPL) v2.1 or, at your option,
+ * any later version. This means you can use it in proprietary products.
+ * See the LICENSE.md file distributed with this source code for details.
+ * @license BSD-3-Clause
+ * @license LGPL-2.1-or-later
+ *
+ * @copyright 2000-2013 John Lim
+ * @copyright 2014 Damien Regad, Mark Newnham and the ADOdb community
+ */
 
 $ADODB_LANG_ARRAY = array (
 			'LANG'                      => 'en',
diff --git a/lib/adodb/readme_moodle.txt b/lib/adodb/readme_moodle.txt
index fcbbf05e35f..26b872986cb 100644
--- a/lib/adodb/readme_moodle.txt
+++ b/lib/adodb/readme_moodle.txt
@@ -1,4 +1,4 @@
-Description of ADOdb v5.21.0 library import into Moodle 3.11 and up
+Description of ADOdb v5.21.4 library import into Moodle 4.0 and up
 
 Source: https://github.com/ADOdb/ADOdb
 
@@ -14,15 +14,12 @@ Removed:
  * lang/* everything but adodb-en.inc.php (originally because they were not utf-8, now because of not used)
  * nbproject/ (if present)
  * pear/
- * replicate/
- * scripts/
+ * replicate/ (if present)
+ * scripts/ (if present)
  * server.php
  * session/
- * tests/
+ * tests/ (if present)
 
 Added:
  * index.html - prevent directory browsing on misconfigured servers
  * readme_moodle.txt - this file ;-)
-
-Our changes (to be checked on next update if they are already applied upstream)::
- * https://github.com/ADOdb/ADOdb/issues/711
diff --git a/lib/thirdpartylibs.xml b/lib/thirdpartylibs.xml
index 4e1bef9172b..329c2978979 100644
--- a/lib/thirdpartylibs.xml
+++ b/lib/thirdpartylibs.xml
@@ -4,7 +4,7 @@
     <location>adodb</location>
     <name>AdoDB</name>
     <license>BSD/LGPL</license>
-    <version>5.21.0</version>
+    <version>5.21.4</version>
     <licenseversion>3-Clause/2.1+</licenseversion>
   </library>
   <library>