diff --git a/lib/kolab_sync_storage.php b/lib/kolab_sync_storage.php
--- a/lib/kolab_sync_storage.php
+++ b/lib/kolab_sync_storage.php
@@ -1928,14 +1928,11 @@
             $this->relations[$folderid][$synctime] = $relations;
             $data = rcube_charset::clean(json_encode($relations));
 
-            $result = $db->query(
-                "INSERT INTO `syncroton_relations_state`"
-                . " (`device_id`, `folder_id`, `synctime`, `data`)"
-                . " VALUES (?, ?, ?, ?)",
-                $device_key,
-                $folderid,
-                $synctime,
-                $data
+            $result = $db->insert_or_update(
+                'syncroton_relations_state',
+                ['device_id' => $device_key, 'folder_id' => $folderid, 'synctime' => $synctime],
+                ['data'],
+                [$data]
             );
 
             if ($err = $db->is_error($result)) {