diff --git a/app/Models/db_upgrades/db_5.2.0.php b/app/Models/db_upgrades/db_5.2.0.php
index 9ad67403a..0c7cdfd01 100644
--- a/app/Models/db_upgrades/db_5.2.0.php
+++ b/app/Models/db_upgrades/db_5.2.0.php
@@ -1,6 +1,20 @@
 <?php
 $output .= "Upgrade database to 5.2.0 commenced.\n\n";
 
+if ($db->fieldExists('user_id', 'change_log')) {
+    $sql = "ALTER TABLE `change_log` DROP `user_id`";
+    $db->query($sql);
+    $output .= str_replace("\n", " ", (string)$db->getLastQuery()) . "\n\n";
+    log_message('info', (string)$db->getLastQuery());
+}
+
+if (!$db->fieldExists('ack_by', 'change_log')) {
+    $sql = "ALTER TABLE `change_log` ADD `ack_by` varchar(200) NOT NULL DEFAULT ''";
+    $db->query($sql);
+    $output .= str_replace("\n", " ", (string)$db->getLastQuery()) . "\n\n";
+    log_message('info', (string)$db->getLastQuery());
+}
+
 $sql = "DELETE FROM `configuration` WHERE `name` IN ('product', 'oae_product')";
 $db->query($sql);
 $output .= str_replace("\n", " ", (string)$db->getLastQuery()) . "\n\n";
diff --git a/other/open-audit.sql b/other/open-audit.sql
index c1b8491a7..9c1a810c7 100644
--- a/other/open-audit.sql
+++ b/other/open-audit.sql
@@ -557,7 +557,7 @@ CREATE TABLE `change_log` (
   `db_row` int(10) unsigned NOT NULL DEFAULT '0',
   `db_action` enum('','create','update','delete') NOT NULL DEFAULT '',
   `details` text NOT NULL,
-  `user_id` int(10) unsigned DEFAULT NULL,
+  `ack_by` varchar(200) NOT NULL DEFAULT '',
   `ack_time` datetime NOT NULL DEFAULT '2000-01-01 00:00:00',
   `external_link` varchar(200) NOT NULL DEFAULT '',
   `external_ident` varchar(200) NOT NULL DEFAULT '',