diff --git a/wp-admin/includes/update-core.php b/wp-admin/includes/update-core.php
index 2e2b303bbd..9aac1e77b7 100644
--- a/wp-admin/includes/update-core.php
+++ b/wp-admin/includes/update-core.php
@@ -250,7 +250,10 @@ function update_core($from, $to) {
 	$wp_filesystem->delete($from, true);
 
 	// Force refresh of update information
-	delete_transient('update_core');
+	if ( function_exists('delete_transient') )
+		delete_transient('update_core');
+	else
+		delete_option('update_core');
 
 	// Remove maintenance file, we're done.
 	$wp_filesystem->delete($maintenance_file);