diff --git a/includes/Service.php b/includes/Service.php
index b61643d..e52b627 100644
--- a/includes/Service.php
+++ b/includes/Service.php
@@ -52,7 +52,7 @@ public function is_enabled() {
 	 *
 	 * @return void
 	 */
-	public function last_changed_timestamp() {
+	private function last_changed_timestamp() {
 		update_option( 'nfd_coming_soon_last_changed', time() );
 	}