diff --git a/phpBB/includes/constants.php b/phpBB/includes/constants.php
index 3304194cf4..0ef409767d 100644
--- a/phpBB/includes/constants.php
+++ b/phpBB/includes/constants.php
@@ -152,9 +152,13 @@ define('FULL_FOLDER_DELETE', -2);
 define('FULL_FOLDER_HOLD', -1);
 
 // Confirm types
+/** @deprecated 4.0.0-a1 Replaced by \phpbb\captcha\plugins\plugin_interface::CONFIRM_REGISTRATION, to be removed in 5.0.0-a1 */
 define('CONFIRM_REG', 1);
+/** @deprecated 4.0.0-a1 Replaced by \phpbb\captcha\plugins\plugin_interface::CONFIRM_LOGIN, to be removed in 5.0.0-a1 */
 define('CONFIRM_LOGIN', 2);
+/** @deprecated 4.0.0-a1 Replaced by \phpbb\captcha\plugins\plugin_interface::CONFIRM_POST, to be removed in 5.0.0-a1 */
 define('CONFIRM_POST', 3);
+/** @deprecated 4.0.0-a1 Replaced by \phpbb\captcha\plugins\plugin_interface::CONFIRM_REPORT, to be removed in 5.0.0-a1 */
 define('CONFIRM_REPORT', 4);
 
 // Categories - Attachments