diff --git a/index.php b/index.php
index 9acd7ed7..a56219cf 100644
--- a/index.php
+++ b/index.php
@@ -37,7 +37,7 @@ class LogException extends \Exception {
 }
 
 class RecursiveDirectoryIteratorWithoutData extends \RecursiveFilterIterator {
-	public function accept() {
+	public function accept(): bool {
 		/** @var \DirectoryIterator $this */
 		$excludes = [
 			'.rnd',