diff --git a/src/Composer/VersionComparator.php b/src/Composer/VersionComparator.php
index ebf1632..a780054 100644
--- a/src/Composer/VersionComparator.php
+++ b/src/Composer/VersionComparator.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 namespace Rector\Jack\Composer;
 
 final class VersionComparator