diff --git a/core/upgrade/upgrade_schema.php b/core/upgrade/upgrade_schema.php
index 37bc34d518..ec87579281 100644
--- a/core/upgrade/upgrade_schema.php
+++ b/core/upgrade/upgrade_schema.php
@@ -34,6 +34,7 @@
 		$document_root = $matches[1];
 		set_include_path($document_root);
 		require_once "resources/require.php";
+		require_once "resources/classes/text.php";
 		$_SERVER["DOCUMENT_ROOT"] = $document_root;
 		$format = 'text'; //html, text
 
@@ -70,4 +71,4 @@ if (!$included && $format == 'html') {
 	require_once "resources/footer.php";
 }
 
-?>
\ No newline at end of file
+?>