diff --git a/src/Plugin/Block/AddActivity.php b/src/Plugin/Block/AddActivity.php
index 0f32ce5..84b7d0a 100644
--- a/src/Plugin/Block/AddActivity.php
+++ b/src/Plugin/Block/AddActivity.php
@@ -1,4 +1,4 @@
-<?php
+<?php declare(strict_types = 1);
 
 namespace Drupal\opencase\Plugin\Block;