diff --git a/libertree/libertree.php b/libertree/libertree.php
index a7dcce58..34fcd798 100644
--- a/libertree/libertree.php
+++ b/libertree/libertree.php
@@ -6,6 +6,7 @@
  * Author: Tony Baldwin <https://free-haven.org/u/tony>
  */
 
+use Friendica\App;
 use Friendica\Content\Text\BBCode;
 use Friendica\Core\Addon;
 use Friendica\Core\L10n;