diff --git a/multi-post-thumbnails.php b/multi-post-thumbnails.php
index 898b200..1d6529e 100644
--- a/multi-post-thumbnails.php
+++ b/multi-post-thumbnails.php
@@ -27,6 +27,7 @@
 
 if (!class_exists('MultiPostThumbnails')) {
 
+	#[\AllowDynamicProperties]
 	class MultiPostThumbnails {
 
 		/**