diff --git a/core/components/simplesearch/model/simplesearch/simplesearch.class.php b/core/components/simplesearch/model/simplesearch/simplesearch.class.php
index 109bf01..4860825 100644
--- a/core/components/simplesearch/model/simplesearch/simplesearch.class.php
+++ b/core/components/simplesearch/model/simplesearch/simplesearch.class.php
@@ -344,7 +344,7 @@ public function sanitize($text) {
      * @return string The generated extract.
      */
     public function createExtract($text, $length = 200, $search = '', $ellipsis = '...') {
-        $text = trim(preg_replace('/\s+/', ' ', $this->sanitize($text)));
+        $text = trim(preg_replace('/\s+/u', ' ', $this->sanitize($text)));
         if (empty($text)) {
             return '';
         }